Avoid a crash in realloc() if the allocation of the new block failed. Return NULL instead.

Someone please review. Should errno be set to ENOMEM here?

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@21903 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/libroot/posix/malloc/wrapper.cpp

@@ -285,6 +285,11 @@ realloc(void *ptr, size_t size)
 
 	// Allocate a new block of size sz.
 	void *buffer = malloc(size);
+	if (buffer == NULL) {
+		// Allocation failed, free old block and return
+		free(ptr);
+		return NULL;
+	}
 
 	// Copy the contents of the original object
 	// up to the size of the new block.