Fix switchmap during switch character crash (@toevent)

use @toevent, then switch character (and stay on character screen).

Thread 1 "manaplus" received signal SIGSEGV, Segmentation fault.
0x.. in Game::getCurrentMap (this=<optimized out>) at ./game.h:108
108             { return mCurrentMap; }

(gdb) bt
0x.. in Game::getCurrentMap (this=<optimized out>) at ./game.h:108
Ea::PlayerRecv::processMapMask (msg=...) at net/ea/playerrecv.cpp:242

****
mana/plus!108

1 files changed, 6 insertions, 1 deletions

diff --git a/src/net/ea/playerrecv.cpp b/src/net/ea/playerrecv.cpp
index b0b9bab70..b4bbc9ce4 100644
--- a/src/net/ea/playerrecv.cpp
+++ b/src/net/ea/playerrecv.cpp
@@ -239,7 +239,12 @@ void PlayerRecv::processMapMask(Net::MessageIn &msg)
 {
     const int mask = msg.readInt32("mask");
     msg.readInt32("unused");
-    Map *const map = Game::instance()->getCurrentMap();
+
+    const Game *const game = Game::instance();
+    if (game == nullptr)
+        return;
+
+    Map *const map = game->getCurrentMap();
     if (map != nullptr)
         map->setMask(mask);
 }