From f228676966ca3208a5d07050e7cef51079cd1025 Mon Sep 17 00:00:00 2001
From: Magnus Jacobsson <magnus.jacobsson@berotec.se>
Date: Fri, 2 Oct 2020 14:57:42 +0200
Subject: [PATCH] Show usage and exit non-zero for unsupported option in gc

Towards https://gitlab.com/graphviz/graphviz/-/issues/1843.
---
 cmd/tools/gc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/cmd/tools/gc.c b/cmd/tools/gc.c
index 5b9e8e783..840fbb5f6 100644
--- a/cmd/tools/gc.c
+++ b/cmd/tools/gc.c
@@ -125,9 +125,11 @@ static void init(int argc, char *argv[])
 	case '?':
 	    if (optopt == '?')
 		usage(0);
-	    else
-		fprintf(stderr, "gc: option -%c unrecognized - ignored\n",
+	    else {
+		fprintf(stderr, "gc: option -%c unrecognized\n",
 			optopt);
+		usage(1);
+	    }
 	    break;
 	}
     }
-- 
2.40.0