Allow to have both WinMain and main defined on Windows

sokol_app.h

@@ -27,13 +27,14 @@
 
     Optionally provide the following defines with your own implementations:
 
-        SOKOL_ASSERT(c)     - your own assert macro (default: assert(c))
-        SOKOL_UNREACHABLE() - a guard macro for unreachable code (default: assert(false))
-        SOKOL_WIN32_FORCE_MAIN  - define this on Win32 to use a main() entry point instead of WinMain
-        SOKOL_NO_ENTRY      - define this if sokol_app.h shouldn't "hijack" the main() function
-        SOKOL_APP_API_DECL  - public function declaration prefix (default: extern)
-        SOKOL_API_DECL      - same as SOKOL_APP_API_DECL
-        SOKOL_API_IMPL      - public function implementation prefix (default: -)
+        SOKOL_ASSERT(c)             - your own assert macro (default: assert(c))
+        SOKOL_UNREACHABLE()         - a guard macro for unreachable code (default: assert(false))
+        SOKOL_WIN32_FORCE_MAIN      - define this on Win32 to add a main() entry point
+        SOKOL_WIN32_FORCE_WINMAIN   - define this on Win32 to add a WinMain() entry point (enabled by default unless SOKOL_WIN32_FORCE_MAIN or SOKOL_NO_ENTRY is defined)
+        SOKOL_NO_ENTRY              - define this if sokol_app.h shouldn't "hijack" the main() function
+        SOKOL_APP_API_DECL          - public function declaration prefix (default: extern)
+        SOKOL_API_DECL              - same as SOKOL_APP_API_DECL
+        SOKOL_API_IMPL              - public function implementation prefix (default: -)
 
     Optionally define the following to force debug checks and validations
     even in release mode:
@@ -8155,7 +8156,8 @@ int main(int argc, char* argv[]) {
     _sapp_win32_run(&desc);
     return 0;
 }
-#else
+#endif /* SOKOL_WIN32_FORCE_MAIN */
+#if defined(SOKOL_WIN32_FORCE_WINMAIN) || !defined(SOKOL_WIN32_FORCE_MAIN)
 int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _In_ LPSTR lpCmdLine, _In_ int nCmdShow) {
     _SOKOL_UNUSED(hInstance);
     _SOKOL_UNUSED(hPrevInstance);
@@ -8168,7 +8170,7 @@ int WINAPI WinMain(_In_ HINSTANCE hInstance, _In_opt_ HINSTANCE hPrevInstance, _
     _sapp_free(argv_utf8);
     return 0;
 }
-#endif /* SOKOL_WIN32_FORCE_MAIN */
+#endif /* SOKOL_WIN32_FORCE_WINMAIN */
 #endif /* SOKOL_NO_ENTRY */
 
 #ifdef _MSC_VER