main.cpp: Define SDL_MAIN_HANDLED

According to the documentation [1], SDL.h defines `main` as a macro
so as to perform automatic initialization and replaces the main
function with `SDL_main`. In order to avoid this behaviour, the
SDL_MAIN_HANDLED macro must be defined before including SDL.h.

This commit solves link-time undefined references to `main`.

[1]: https://wiki.libsdl.org/SDL2/SDL_SetMainReady


git-svn-id: https://svn.code.sf.net/p/speed-dreams/code/trunk@9557 30fe4595-0a0c-4342-8851-515496e4dcbd

Former-commit-id: dc524d945dab929872060470a1073de283064883
Former-commit-id: e316320adb8e8697167f281a79968fd65af23327

src/main/main.cpp

@@ -16,6 +16,8 @@
  *                                                                         *
  ***************************************************************************/
 
+#define SDL_MAIN_HANDLED
+
 #include <string>
 #include <iostream>
 #include <sstream>

src/tools/menuview/main.cpp

@@ -16,6 +16,8 @@
  *                                                                         *
  ***************************************************************************/
 
+#define SDL_MAIN_HANDLED
+
 #include <portability.h>
 
 #include <string>