Add missing error handling.

git-svn-id: svn://svn.code.sf.net/p/sc2/code/trunk@3301 8092fc87-c524-0410-9efc-e669fe64eaf9

sc2/src/libs/graphics/drawable.c

@@ -91,6 +91,11 @@ AllocDrawable (COUNT n)
 	{
 		int i;
 		Drawable->Frame = (FRAME)HMalloc (sizeof (FRAME_DESC) * n);
+		if (Drawable->Frame == NULL)
+		{
+			HFree (Drawable);
+			return NULL;
+		}
 
 		/* Zero out the newly allocated frames, since HMalloc doesn't have
 		 * MEM_ZEROINIT. */