tools/fast: fix -skip-unused

Author: medvednikov

cmd/tools/fast/fast.v

@@ -39,7 +39,7 @@ fn main() {
 	println('  Building vprod...')
 	exec('v -o $vdir/vprod -prod -prealloc $vdir/cmd/v')
 	// exec('v -o $vdir/vprod $vdir/cmd/v') // for faster debugging
-	diff1 := measure('$vdir/vprod -cc -skip-unused clang -o v.c -show-timings $vdir/cmd/v', 'v.c')
+	diff1 := measure('$vdir/vprod -skip-unused -cc clang -o v.c -show-timings $vdir/cmd/v', 'v.c')
 	mut tcc_path := 'tcc'
 	$if freebsd {
 		tcc_path = '/usr/local/bin/tcc'