Change namelen to size_t because it is always unsigned and less in size than size_t

Author: nielsdos

ext/session/session.c

@@ -904,10 +904,9 @@ PS_SERIALIZER_DECODE_FUNC(php_binary) /* {{{ */
 	PHP_VAR_UNSERIALIZE_INIT(var_hash);
 
 	for (p = val; p < endptr; ) {
-		// Can this be changed to size_t?
-		int namelen = ((unsigned char)(*p)) & (~PS_BIN_UNDEF);
+		size_t namelen = ((unsigned char)(*p)) & (~PS_BIN_UNDEF);
 
-		if (namelen < 0 || namelen > PS_BIN_MAX || (p + namelen) >= endptr) {
+		if (namelen > PS_BIN_MAX || (p + namelen) >= endptr) {
 			PHP_VAR_UNSERIALIZE_DESTROY(var_hash);
 			return FAILURE;
 		}