Fixed some additional linux warnings

- Fixed some warnings we had missed.
- Improved -W cflag detection routines.
- Only use -Wshadow if it's actually useful.

Signed-off-by: Haru <haru@dotalux.com>

3 files changed, 808 insertions, 334 deletions

diff --git a/configure b/configure
index 28c9f9361..7142ed479 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.in 547ee9a.
+# From configure.in d0f16b7.
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.69.
 #
@@ -3643,12 +3643,12 @@ fi
 # Check whether --enable-lto was given.
 if test "${enable_lto+set}" = set; then :
   enableval=$enable_lto;
-        enable_lto="$enableval"
-        case $enableval in
-            "no");;
-            "yes");;
-            *) as_fn_error $? "invalid argument --enable-lto=$disableval... stopping" "$LINENO" 5;;
-        esac
+		enable_lto="$enableval"
+		case $enableval in
+			"no");;
+			"yes");;
+			*) as_fn_error $? "invalid argument --enable-lto=$disableval... stopping" "$LINENO" 5;;
+		esac
 
 else
   enable_lto="yes"
@@ -4924,28 +4924,6 @@ fi
 
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-unused-parameter" >&5
-$as_echo_n "checking whether $CC supports -Wno-unused-parameter... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-unused-parameter"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-int foo;
-_ACEOF
-if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-else
-
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
-$as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
-
-
-fi
-rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
-
-
 #
 # LTO Support test
 #
@@ -4970,8 +4948,8 @@ else
 /* end confdefs.h.  */
 
 			int main(int argc, char **argv){
-               return 0;
-           }
+				return 0;
+			}
 
 _ACEOF
 if ac_fn_c_try_run "$LINENO"; then :
@@ -4994,320 +4972,881 @@ fi
 fi
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-maybe-uninitialized" >&5
-$as_echo_n "checking whether $CC supports -Wno-maybe-uninitialized... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-maybe-uninitialized"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+
+
+
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-unused-parameter" >&5
+$as_echo_n "checking whether $CC supports -Wno-unused-parameter... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-unused-parameter"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-maybe-uninitialized" >&5
-$as_echo_n "checking whether $CC can actually use -Wno-maybe-uninitialized... " >&6; }
-		# Note: -Werror must be before -Wno-maybe-uninitialized, otherwise it does not do anything
-		CFLAGS="$OLD_CFLAGS -Werror -Wno-maybe-uninitialized"
-		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -Wunused-parameter"
+				cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
 
-				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
-				CFLAGS="$OLD_CFLAGS -Wno-maybe-uninitialized"
+						CFLAGS="$OLD_CFLAGS -Wno-unused-parameter"
+						# Optionally, run a test
+						if test "xint foo(int bar) { return 0; }" != "x"; then
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-unused-parameter" >&5
+$as_echo_n "checking whether $CC can actually use -Wno-unused-parameter... " >&6; }
+							CFLAGS="$OLD_CFLAGS -Werror -Wunused-parameter"
+							cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo(int bar) { return 0; }
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+									{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not needed but enabled" >&5
+$as_echo "not needed but enabled" >&6; }
+									CFLAGS="$OLD_CFLAGS"
 
 else
 
-				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-unused-parameter"
+									cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo(int bar) { return 0; }
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+											CFLAGS="$OLD_CFLAGS -Wno-unused-parameter"
+
+else
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-				CFLAGS="$OLD_CFLAGS"
+											CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+						fi
 
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+						CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+else
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-clobbered" >&5
-$as_echo_n "checking whether $CC supports -Wno-clobbered... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-clobbered"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-maybe-uninitialized" >&5
+$as_echo_n "checking whether $CC supports -Wno-maybe-uninitialized... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-maybe-uninitialized"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
-$as_echo "yes" >&6; }
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-clobbered" >&5
-$as_echo_n "checking whether $CC can actually use -Wno-clobbered... " >&6; }
-		# Note: -Werror must be before -Wno-clobbered, otherwise it does not do anything
-		CFLAGS="$OLD_CFLAGS -Werror -Wno-clobbered"
-		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -Wmaybe-uninitialized"
+				cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
 
-				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
-				CFLAGS="$OLD_CFLAGS -Wno-clobbered"
+						CFLAGS="$OLD_CFLAGS -Wno-maybe-uninitialized"
+						# Optionally, run a test
+						if test "x" != "x"; then
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-maybe-uninitialized" >&5
+$as_echo_n "checking whether $CC can actually use -Wno-maybe-uninitialized... " >&6; }
+							CFLAGS="$OLD_CFLAGS -Werror -Wmaybe-uninitialized"
+							cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+									{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not needed but enabled" >&5
+$as_echo "not needed but enabled" >&6; }
+									CFLAGS="$OLD_CFLAGS"
 
 else
 
-				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-maybe-uninitialized"
+									cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+											CFLAGS="$OLD_CFLAGS -Wno-maybe-uninitialized"
+
+else
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-				CFLAGS="$OLD_CFLAGS"
+											CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+						fi
 
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+						CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
+else
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wempty-body" >&5
-$as_echo_n "checking whether $CC supports -Wempty-body... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wempty-body"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-clobbered" >&5
+$as_echo_n "checking whether $CC supports -Wno-clobbered... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-clobbered"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -Wclobbered"
+				cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo;
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+						CFLAGS="$OLD_CFLAGS -Wno-clobbered"
+						# Optionally, run a test
+						if test "x" != "x"; then
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-clobbered" >&5
+$as_echo_n "checking whether $CC can actually use -Wno-clobbered... " >&6; }
+							CFLAGS="$OLD_CFLAGS -Werror -Wclobbered"
+							cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+									{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not needed but enabled" >&5
+$as_echo "not needed but enabled" >&6; }
+									CFLAGS="$OLD_CFLAGS"
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-clobbered"
+									cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+											CFLAGS="$OLD_CFLAGS -Wno-clobbered"
+
+else
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+											CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wnewline-eof" >&5
-$as_echo_n "checking whether $CC supports -Wnewline-eof... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wnewline-eof"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+						fi
+
+else
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+						CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+else
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wempty-body" >&5
+$as_echo_n "checking whether $CC supports -Wempty-body... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wempty-body"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wempty-body"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wempty-body" >&5
+$as_echo_n "checking whether $CC can actually use -Wempty-body... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wempty-body"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wempty-body"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wshadow" >&5
-$as_echo_n "checking whether $CC supports -Wshadow... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wshadow"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wnewline-eof" >&5
+$as_echo_n "checking whether $CC supports -Wnewline-eof... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wnewline-eof"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wnewline-eof"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wnewline-eof" >&5
+$as_echo_n "checking whether $CC can actually use -Wnewline-eof... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wnewline-eof"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wnewline-eof"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wint-conversion" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wint-conversion" >&5
 $as_echo_n "checking whether $CC supports -Wint-conversion... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wenum-conversion"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wint-conversion"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wint-conversion"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wint-conversion" >&5
+$as_echo_n "checking whether $CC can actually use -Wint-conversion... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wint-conversion"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wint-conversion"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wenum-conversion" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wenum-conversion" >&5
 $as_echo_n "checking whether $CC supports -Wenum-conversion... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wenum-conversion"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wenum-conversion"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wenum-conversion"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wenum-conversion" >&5
+$as_echo_n "checking whether $CC can actually use -Wenum-conversion... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wenum-conversion"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wenum-conversion"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wshorten-64-to-32" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wshorten-64-to-32" >&5
 $as_echo_n "checking whether $CC supports -Wshorten-64-to-32... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wshorten-64-to-32"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wshorten-64-to-32"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wshorten-64-to-32"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wshorten-64-to-32" >&5
+$as_echo_n "checking whether $CC can actually use -Wshorten-64-to-32... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wshorten-64-to-32"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wshorten-64-to-32"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wconstant-conversion" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wconstant-conversion" >&5
 $as_echo_n "checking whether $CC supports -Wconstant-conversion... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wconstant-conversion"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wconstant-conversion"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wconstant-conversion"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wconstant-conversion" >&5
+$as_echo_n "checking whether $CC can actually use -Wconstant-conversion... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wconstant-conversion"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wconstant-conversion"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wbool-conversion" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wbool-conversion" >&5
 $as_echo_n "checking whether $CC supports -Wbool-conversion... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wbool-conversion"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wbool-conversion"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wbool-conversion"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wbool-conversion" >&5
+$as_echo_n "checking whether $CC can actually use -Wbool-conversion... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wbool-conversion"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wbool-conversion"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-switch" >&5
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-switch" >&5
 $as_echo_n "checking whether $CC supports -Wno-switch... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-switch"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-switch"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -Wswitch"
+				cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo;
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+						CFLAGS="$OLD_CFLAGS -Wno-switch"
+						# Optionally, run a test
+						if test "x" != "x"; then
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-switch" >&5
+$as_echo_n "checking whether $CC can actually use -Wno-switch... " >&6; }
+							CFLAGS="$OLD_CFLAGS -Werror -Wswitch"
+							cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+									{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not needed but enabled" >&5
+$as_echo "not needed but enabled" >&6; }
+									CFLAGS="$OLD_CFLAGS"
+
+else
+
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-switch"
+									cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+											CFLAGS="$OLD_CFLAGS -Wno-switch"
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+											CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-missing-field-initializers" >&5
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+						fi
+
+else
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+						CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+else
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wno-missing-field-initializers" >&5
 $as_echo_n "checking whether $CC supports -Wno-missing-field-initializers... " >&6; }
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-missing-field-initializers"
-cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-missing-field-initializers"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 int foo;
 _ACEOF
 if ac_fn_c_try_compile "$LINENO"; then :
-  { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -Wmissing-field-initializers"
+				cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo;
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+						CFLAGS="$OLD_CFLAGS -Wno-missing-field-initializers"
+						# Optionally, run a test
+						if test "x" != "x"; then
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wno-missing-field-initializers" >&5
+$as_echo_n "checking whether $CC can actually use -Wno-missing-field-initializers... " >&6; }
+							CFLAGS="$OLD_CFLAGS -Werror -Wmissing-field-initializers"
+							cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+									{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not needed but enabled" >&5
+$as_echo "not needed but enabled" >&6; }
+									CFLAGS="$OLD_CFLAGS"
+
+else
+
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-missing-field-initializers"
+									cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
+											CFLAGS="$OLD_CFLAGS -Wno-missing-field-initializers"
+
 else
 
-		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+											{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-		CFLAGS="$OLD_CFLAGS"
+											CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+						fi
+
+else
+
+						{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+						CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+else
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+
+
+
+# Certain versions of gcc make -Wshadow completely useless by making it flood
+# you with unnecessary warnings <https://lkml.org/lkml/2006/11/28/239>
+# Let's check if we can really use it
+SAVED_OLD_CFLAGS="$CFLAGS"
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -Wshadow" >&5
+$as_echo_n "checking whether $CC supports -Wshadow... " >&6; }
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wshadow"
+		cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+int foo;
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+				CFLAGS="$OLD_CFLAGS -Wshadow"
+				# Optionally, run a test
+				if test "x" != "x"; then
+					{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can actually use -Wshadow" >&5
+$as_echo_n "checking whether $CC can actually use -Wshadow... " >&6; }
+					CFLAGS="$OLD_CFLAGS -Werror -Wshadow"
+					cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+							CFLAGS="$OLD_CFLAGS"
+
+
+							{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+							CFLAGS="$OLD_CFLAGS -Wshadow"
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+				fi
+
+else
+
+				{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+				CFLAGS="$OLD_CFLAGS"
 
 
 fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
+if test "x$CFLAGS" != "x$SAVED_OLD_CFLAGS"; then
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC can efficiently use -Wshadow" >&5
+$as_echo_n "checking whether $CC can efficiently use -Wshadow... " >&6; }
+	NEW_CFLAGS="$CFLAGS"
+	CFLAGS="$CFLAGS -Werror -Wshadow"
+	cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+			int foo(void) {
+				return 0;
+			}
+			int bar(void) {
+				int foo = 0;
+				return foo + 1;
+			}
+
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+$as_echo "yes" >&6; }
+			CFLAGS="$NEW_CFLAGS"
+
+else
+
+			{ $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
+			CFLAGS="$SAVED_OLD_CFLAGS"
+
+
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+fi
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC supports -fPIC" >&5
 $as_echo_n "checking whether $CC supports -fPIC... " >&6; }
 OLD_CFLAGS="$CFLAGS"
diff --git a/configure.in b/configure.in
index e8e2eba3f..94bad9ca4 100644
--- a/configure.in
+++ b/configure.in
@@ -248,22 +248,22 @@ AC_ARG_ENABLE(
 # LTO
 #
 AC_ARG_ENABLE(
-    [lto],
-    AC_HELP_STRING(
-        [--enable-lto],
-        [
+	[lto],
+	AC_HELP_STRING(
+		[--enable-lto],
+		[
 			Enables or Disables Linktime Code Optimization (LTO is enabled by default)
-        ]
-    ),
-    [
-        enable_lto="$enableval"
-        case $enableval in
-            "no");;
-            "yes");;
-            *) AC_MSG_ERROR([[invalid argument --enable-lto=$disableval... stopping]]);;
-        esac
-    ],
-    [enable_lto="yes"]
+		]
+	),
+	[
+		enable_lto="$enableval"
+		case $enableval in
+			"no");;
+			"yes");;
+			*) AC_MSG_ERROR([[invalid argument --enable-lto=$disableval... stopping]]);;
+		esac
+	],
+	[enable_lto="yes"]
 )
 
 
@@ -517,19 +517,6 @@ AC_RUN_IFELSE(
 )
 
 
-AC_MSG_CHECKING([whether $CC supports -Wno-unused-parameter])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-unused-parameter"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
 #
 # LTO Support test
 #
@@ -545,8 +532,8 @@ if test "$enable_lto" != "no" ; then
 	AC_RUN_IFELSE(
 		[AC_LANG_SOURCE([
 			int main(int argc, char **argv){
-               return 0;
-           }
+				return 0;
+			}
 		])],
 		[
 			AC_MSG_RESULT([yes])
@@ -563,193 +550,141 @@ if test "$enable_lto" != "no" ; then
 fi
 
 
-AC_MSG_CHECKING([whether $CC supports -Wno-maybe-uninitialized])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-maybe-uninitialized"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
+AC_DEFUN(AC_CHECK_COMPILER_WFLAG,
 	[
-		AC_MSG_RESULT([yes])
-		AC_MSG_CHECKING([whether $CC can actually use -Wno-maybe-uninitialized])
-		# Note: -Werror must be before -Wno-maybe-uninitialized, otherwise it does not do anything
-		CFLAGS="$OLD_CFLAGS -Werror -Wno-maybe-uninitialized"
+		AC_MSG_CHECKING([whether $CC supports -W$1])
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -W$1"
 		AC_COMPILE_IFELSE(
 			[AC_LANG_SOURCE([int foo;])],
 			[
 				AC_MSG_RESULT([yes])
-				CFLAGS="$OLD_CFLAGS -Wno-maybe-uninitialized"
+				CFLAGS="$OLD_CFLAGS -W$1"
+				# Optionally, run a test
+				if test "x$2" != "x"; then
+					AC_MSG_CHECKING([whether $CC can actually use -W$1])
+					CFLAGS="$OLD_CFLAGS -Werror -W$1"
+					AC_COMPILE_IFELSE(
+						[AC_LANG_SOURCE([$2])],
+						[
+							AC_MSG_RESULT([no])
+							CFLAGS="$OLD_CFLAGS"
+						]
+						[
+							AC_MSG_RESULT([yes])
+							CFLAGS="$OLD_CFLAGS -W$1"
+						],
+					)
+				fi
 			],
 			[
 				AC_MSG_RESULT([no])
 				CFLAGS="$OLD_CFLAGS"
 			]
 		)
-	],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
 	]
 )
 
-
-AC_MSG_CHECKING([whether $CC supports -Wno-clobbered])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-clobbered"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
+AC_DEFUN(AC_CHECK_COMPILER_WNOFLAG,
 	[
-		AC_MSG_RESULT([yes])
-		AC_MSG_CHECKING([whether $CC can actually use -Wno-clobbered])
-		# Note: -Werror must be before -Wno-clobbered, otherwise it does not do anything
-		CFLAGS="$OLD_CFLAGS -Werror -Wno-clobbered"
+		AC_MSG_CHECKING([whether $CC supports -Wno-$1])
+		OLD_CFLAGS="$CFLAGS"
+		CFLAGS="$CFLAGS -Werror -Wno-$1"
 		AC_COMPILE_IFELSE(
 			[AC_LANG_SOURCE([int foo;])],
 			[
-				AC_MSG_RESULT([yes])
-				CFLAGS="$OLD_CFLAGS -Wno-clobbered"
+				# Recent versions of gcc don't fail if -Wno-foo is not recognized
+				# (unless there are also other warnings), so we also check for -Wfoo
+				# which always fails if not supported
+				CFLAGS="$OLD_CFLAGS -Werror -W$1"
+				AC_COMPILE_IFELSE(
+					[AC_LANG_SOURCE([int foo;])],
+					[
+						AC_MSG_RESULT([yes])
+						CFLAGS="$OLD_CFLAGS -Wno-$1"
+						# Optionally, run a test
+						if test "x$2" != "x"; then
+							AC_MSG_CHECKING([whether $CC can actually use -Wno-$1])
+							CFLAGS="$OLD_CFLAGS -Werror -W$1"
+							AC_COMPILE_IFELSE(
+								[AC_LANG_SOURCE([$2])],
+								[
+									AC_MSG_RESULT([not needed but enabled])
+									CFLAGS="$OLD_CFLAGS"
+								],
+								[
+									CFLAGS="$OLD_CFLAGS -Werror -Wno-$1"
+									AC_COMPILE_IFELSE(
+										[AC_LANG_SOURCE([$2])],
+										[
+											AC_MSG_RESULT([yes])
+											CFLAGS="$OLD_CFLAGS -Wno-$1"
+										],
+										[
+											AC_MSG_RESULT([no])
+											CFLAGS="$OLD_CFLAGS"
+										]
+									)
+								]
+							)
+						fi
+					],
+					[
+						AC_MSG_RESULT([no])
+						CFLAGS="$OLD_CFLAGS"
+					]
+				)
 			],
 			[
 				AC_MSG_RESULT([no])
 				CFLAGS="$OLD_CFLAGS"
 			]
 		)
-	],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wempty-body])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wempty-body"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wnewline-eof])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wnewline-eof"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wshadow])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wshadow"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wint-conversion])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wenum-conversion"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wenum-conversion])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wenum-conversion"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wshorten-64-to-32])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wshorten-64-to-32"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wconstant-conversion])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wconstant-conversion"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wbool-conversion])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wbool-conversion"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wno-switch])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-switch"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
-	]
-)
-
-
-AC_MSG_CHECKING([whether $CC supports -Wno-missing-field-initializers])
-OLD_CFLAGS="$CFLAGS"
-CFLAGS="$CFLAGS -Wno-missing-field-initializers"
-AC_COMPILE_IFELSE(
-	[AC_LANG_SOURCE([int foo;])],
-	[AC_MSG_RESULT([yes])],
-	[
-		AC_MSG_RESULT([no])
-		CFLAGS="$OLD_CFLAGS"
 	]
 )
 
+AC_CHECK_COMPILER_WNOFLAG(unused-parameter, [int foo(int bar) { return 0; }])
+AC_CHECK_COMPILER_WNOFLAG(maybe-uninitialized)
+AC_CHECK_COMPILER_WNOFLAG(clobbered)
+AC_CHECK_COMPILER_WFLAG(empty-body)
+AC_CHECK_COMPILER_WFLAG(newline-eof)
+AC_CHECK_COMPILER_WFLAG(int-conversion)
+AC_CHECK_COMPILER_WFLAG(enum-conversion)
+AC_CHECK_COMPILER_WFLAG(shorten-64-to-32)
+AC_CHECK_COMPILER_WFLAG(constant-conversion)
+AC_CHECK_COMPILER_WFLAG(bool-conversion)
+AC_CHECK_COMPILER_WNOFLAG(switch)
+AC_CHECK_COMPILER_WNOFLAG(missing-field-initializers)
+
+# Certain versions of gcc make -Wshadow completely useless by making it flood
+# you with unnecessary warnings <https://lkml.org/lkml/2006/11/28/239>
+# Let's check if we can really use it
+SAVED_OLD_CFLAGS="$CFLAGS"
+AC_CHECK_COMPILER_WFLAG(shadow)
+if test "x$CFLAGS" != "x$SAVED_OLD_CFLAGS"; then
+	AC_MSG_CHECKING([whether $CC can efficiently use -Wshadow])
+	NEW_CFLAGS="$CFLAGS"
+	CFLAGS="$CFLAGS -Werror -Wshadow"
+	AC_COMPILE_IFELSE(
+		[AC_LANG_SOURCE([
+			int foo(void) {
+				return 0;
+			}
+			int bar(void) {
+				int foo = 0;
+				return foo + 1;
+			}
+		])],
+		[
+			AC_MSG_RESULT([yes])
+			CFLAGS="$NEW_CFLAGS"
+		],
+		[
+			AC_MSG_RESULT([no])
+			CFLAGS="$SAVED_OLD_CFLAGS"
+		]
+	)
+fi
 
 AC_MSG_CHECKING([whether $CC supports -fPIC])
 OLD_CFLAGS="$CFLAGS"
diff --git a/src/common/timer.c b/src/common/timer.c
index e5cf5df2a..7f9e20dad 100644
--- a/src/common/timer.c
+++ b/src/common/timer.c
@@ -142,7 +142,7 @@ static void rdtsc_calibrate(){
  * platform-abstracted tick retrieval
  * @return server's current tick
  */
-static int64 tick(void) {
+static int64 sys_tick(void) {
 #if defined(WIN32)
 	// Windows: GetTickCount/GetTickCount64: Return the number of
 	//   milliseconds that have elapsed since the system was started.
@@ -206,7 +206,7 @@ static int gettick_count = 1;
 
 int64 timer_gettick_nocache(void) {
 	gettick_count = TICK_CACHE;
-	gettick_cache = tick();
+	gettick_cache = sys_tick();
 	return gettick_cache;
 }
 
@@ -219,11 +219,11 @@ int64 timer_gettick(void) {
 // tick doesn't get cached
 int64 timer_gettick_nocache(void)
 {
-	return tick();
+	return sys_tick();
 }
 
 int64 timer_gettick(void) {
-	return tick();
+	return sys_tick();
 }
 //////////////////////////////////////////////////////////////////////////
 #endif