CLEANUP: dev/flags: remove useless test in the stdin number parser

The test on "if (err)" after parsing a number was meant to be
"if (*err)" but in practise it will always be true since we at least
have a '\n' there, so no need for testing before writing zero.
This fixes issue #1211.

dev/flags/flags.c

@@ -441,7 +441,6 @@ int main(int argc, char **argv)
 			while (*err == '-' || *err == '+' ||
 			       (isalnum((unsigned char)*err) && toupper((unsigned char)*err) != 'U' && toupper((unsigned char)*err) != 'L'))
 				err++;
-			if (err)
 			*err = 0;
 		} else {
 			value = argv[0];