MINOR: new function my_realloc2 = realloc + free upon failure

When realloc fails to allocate memory, the original pointer is not
freed. Sometime people override the original pointer with the pointer
returned by realloc which is NULL in case of failure. This results
in a memory leak because the memory pointed by the original pointer
cannot be freed.

include/common/standard.h

@@ -1093,4 +1093,15 @@ static inline unsigned long long rdtsc()
 struct list;
 int list_append_word(struct list *li, const char *str, char **err);
 
+/* same as realloc() except that ptr is also freed upon failure */
+static inline void *my_realloc2(void *ptr, size_t size)
+{
+	void *ret;
+
+	ret = realloc(ptr, size);
+	if (!ret && size)
+		free(ptr);
+	return ret;
+}
+
 #endif /* _COMMON_STANDARD_H */