Fixing compilation errors related to MUSL libc

Fix Musl libc NULL errors and unsupported pthread funcs for compatibility.
Also ensures cleanup and error handling irrespective of CPU affinity override.

Fix submitted by github dev - AngryLoki
https://github.com/ROCm/ROCR-Runtime/issues/181

Change-Id: Ia487315e504112be5d3370756f23f6e23b9ae4be

runtime/hsa-runtime/image/util.h

@@ -99,7 +99,7 @@ static __forceinline void* _aligned_malloc(size_t size, size_t alignment) {
   return aligned_alloc(alignment, size);
 #else
   void* mem = NULL;
-  if (NULL != posix_memalign(&mem, alignment, size)) return NULL;
+  if (0 != posix_memalign(&mem, alignment, size)) return NULL;
   return mem;
 #endif
 }