thread: Don't use SetThreadDescription on WinRT right now.

Can't LoadLibrary for it, but not sure if it's actually available there yet.

src/thread/windows/SDL_systhread.c

@@ -171,11 +171,12 @@ void
 SDL_SYS_SetupThread(const char *name)
 {
     if (name != NULL) {
-        static HMODULE kernel32 = 0;
+        #ifndef __WINRT__   /* !!! FIXME: There's no LoadLibrary() in WinRT; don't know if SetThreadDescription is available there at all at the moment. */
         static pfnSetThreadDescription pSetThreadDescription = NULL;
+        static HMODULE kernel32 = 0;
 
         if (!kernel32) {
-            kernel32 = LoadLibrary(L"kernel32.dll");
+            kernel32 = LoadLibraryW(L"kernel32.dll");
             if (kernel32) {
                 pSetThreadDescription = (pfnSetThreadDescription) GetProcAddress(kernel32, "SetThreadDescription");
             }
@@ -188,6 +189,7 @@ SDL_SYS_SetupThread(const char *name)
                 SDL_free(strw);
             }
         }
+        #endif
 
         /* Presumably some version of Visual Studio will understand SetThreadDescription(),
            but we still need to deal with older OSes and debuggers. Set it with the arcane