Remove GCC-specific argument specification.

port/strtoull.c

@@ -43,7 +43,7 @@
  * alphabets and digits are each contiguous.
  */
 unsigned long long
-strtoull(const char * __restrict nptr, char ** __restrict endptr, int base)
+strtoull(const char *nptr, char **endptr, int base)
 {
 	const char *s;
 	unsigned long long acc;