Fixed bug #741

The thread ID is an unsigned long so it can hold pthread_t so people can do naughty things with it.

I'm going to be adding additional useful thread API functions, but this should prevent crashes in people's existing code on 64-bit architectures.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%404327

src/thread/nds/SDL_sysmutex.c

@@ -38,7 +38,7 @@ static char rcsid =
 struct SDL_mutex
 {
     int recursive;
-    Uint32 owner;
+    SDL_threadID owner;
     SDL_sem *sem;
 };
 
@@ -84,7 +84,7 @@ SDL_mutexP(SDL_mutex * mutex)
 #ifdef DISABLE_THREADS
     return 0;
 #else
-    Uint32 this_thread;
+    SDL_threadID this_thread;
 
     if (mutex == NULL) {
         SDL_SetError("Passed a NULL mutex");