-my @opts = ("-DCLIENT=$addr", "-DHOST=$host", "-DREPO=$repo");
-push @opts, "-DTILDE=$tilde" if defined $tilde;
-exec 'userv', @opts, $user, 'git-upload-pack'
- or fail "exec userv: $!";
+my @cmd = ('userv', @opts, $user, $service);
+no warnings; # suppress errors to stderr
+exec @cmd or fail "exec userv: $!";