Replaced include guards with #pragma onceHEADmaster

Thanks to https://github.com/cgmb/guardonce and a follow-up replace to
remove duplicated newlines at end of file:

    find src -type f -name '*.h' -exec \
      sed --in-place -e :a -e '/^\n*$/{$d;N;};/\n$/ba' {} \;

Source: https://unix.stackexchange.com/questions/81685/how-to-remove-multiple-newlines-at-eof

Fixes compile on macOS, which appears to have been due to the EVENT_H
include guard.

1 files changed, 1 insertions, 4 deletions

diff --git a/src/utils/sha256.h b/src/utils/sha256.h
index 8a9c2b70..6c2c3107 100644
--- a/src/utils/sha256.h
+++ b/src/utils/sha256.h
@@ -19,8 +19,7 @@
  *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef UTILS_SHA256_H
-#define UTILS_SHA256_H
+#pragma once
 
 #include <string>
 
@@ -31,5 +30,3 @@
  * @return the SHA-256 hash for the given string.
  */
 std::string sha256(const std::string &string);
-
-#endif // UTILS_SHA256_H