MinGW fixes

CMakeLists.txt
* Added definition of SDL_MAIN_HANDLED to solve linking error
src/dsound_compat.h
* Included mmsystem.h for LPCWAVEFORMATEX struct definition
src/file_find.cc
* FindClose is within Win32 API
src/mmx.cc
* __asm keyword is restricted to MSVC

CMakeLists.txt

@@ -272,3 +272,4 @@ target_include_directories(${EXECUTABLE_NAME} PRIVATE ${ZLIB_INCLUDE_DIRS})
 
 target_link_libraries(${EXECUTABLE_NAME} ${SDL2_LIBRARIES})
 target_include_directories(${EXECUTABLE_NAME} PRIVATE ${SDL2_INCLUDE_DIRS})
+add_definitions(-DSDL_MAIN_HANDLED)

src/dsound_compat.h

@@ -9,6 +9,7 @@
 #include <windows.h>
 
 #include <mmreg.h>
+#include <mmsystem.h>
 
 #define DIRECTSOUND_VERSION 0x0300
 #include <dsound.h>

src/file_find.cc

@@ -47,7 +47,7 @@ bool fileFindNext(DirectoryFileFindData* findData)
 // 0x4E63CC
 bool findFindClose(DirectoryFileFindData* findData)
 {
-#if defined(_MSC_VER)
+#if defined(_WIN32)
     FindClose(findData->hFind);
 #else
     if (closedir(findData->dir) != 0) {

src/mmx.cc

@@ -13,7 +13,7 @@ bool mmxIsSupported()
 
     // TODO: There are other ways to determine MMX using FLAGS register.
 
-#ifdef _WIN32
+#if defined (_MSC_VER)
     __asm
     {
         mov eax, 1