Fix tred -? to actually print usage instead of error on macOS

Final commit that fixes https://gitlab.com/graphviz/graphviz/-/issues/1852.

diff --git a/cmd/tools/tred.c b/cmd/tools/tred.c
index 4fec5e874b99c1ca65808d1b7b6bafe8f92b86ab..84b3e308617ba8e2d7eafafa3bc8c481d39cff2b 100644 (file)
--- a/cmd/tools/tred.c
+++ b/cmd/tools/tred.c
@@ -257,7 +257,7 @@ static void init(int argc, char *argv[])
         PrintRemovedEdges = 1;
         break;
        case '?':
-           if (optopt == '\0')
+           if (optopt == '\0' || optopt == '?')
                usage(0);
            else {
                fprintf(stderr, "%s: option -%c unrecognized\n",