windows/SDL_sysfilesystem.c: fix SHGetKnownFolderPath calling convention

src/filesystem/windows/SDL_sysfilesystem.c

@@ -179,7 +179,7 @@ char *SDL_GetPrefPath(const char *org, const char *app)
 
 char *SDL_GetPath(SDL_Folder folder)
 {
-    typedef HRESULT (*pfnSHGetKnownFolderPath)(REFGUID /* REFKNOWNFOLDERID */, DWORD, HANDLE, PWSTR*);
+    typedef HRESULT (WINAPI *pfnSHGetKnownFolderPath)(REFGUID /* REFKNOWNFOLDERID */, DWORD, HANDLE, PWSTR*);
     HMODULE lib = LoadLibrary(L"Shell32.dll");
     pfnSHGetKnownFolderPath pSHGetKnownFolderPath = NULL;
     char *retval = NULL;
@@ -331,7 +331,6 @@ done:
     }
     return retval;
 }
-
 #endif /* SDL_FILESYSTEM_WINDOWS */
 
 #ifdef SDL_FILESYSTEM_XBOX