Fixed other instances of the xrealloc(0) bug.

programs/winetest/util.c

@@ -36,7 +36,7 @@ void *xrealloc (void *op, size_t len)
 {
     void *p = realloc (op, len);
 
-    if (!p) report (R_FATAL, "Out of memory.");
+    if (len && !p) report (R_FATAL, "Out of memory.");
     return p;
 }
 

tools/winegcc/utils.c

@@ -60,8 +60,8 @@ void* xmalloc(size_t size)
 
 void *xrealloc(void* p, size_t size)
 {
-    void* p2;
-    if ((p2 = realloc (p, size)) == NULL)
+    void* p2 = realloc (p, size);
+    if (size && !p2)
 	error("Can not realloc %d bytes.", size);
 
     return p2;