sdlayer: Call SDL_StopTextInput immediately after initialization so IMEs do not interfere with gameplay keypresses.

An example of is on Mac, where holding the 'A' key caused a small overlay with accented forms of the character to appear.

git-svn-id: https://svn.eduke32.com/eduke32@5969 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/build/src/sdlayer.c

@@ -597,6 +597,10 @@ int32_t initsystem(void)
 #endif
     }
 
+#if SDL_MAJOR_VERSION > 1
+    SDL_StopTextInput();
+#endif
+
     atexit(uninitsystem);
 
     frameplace = 0;