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

Towards https://gitlab.com/graphviz/graphviz/-/issues/1852.

diff --git a/cmd/tools/bcomps.c b/cmd/tools/bcomps.c
index a48b73adc3710d8eba3fac7bbcbfeb0e2c6653f5..141b354afd5031985acec1e7c3802e4661d30718 100644 (file)
--- a/cmd/tools/bcomps.c
+++ b/cmd/tools/bcomps.c
@@ -358,7 +358,7 @@ static void init(int argc, char *argv[])
            fprintf(stderr, "bcomps: option -%c missing argument - ignored\n", optopt);
            break;
        case '?':
-           if (optopt == '\0')
+           if (optopt == '\0' || optopt == '?')
                usage(0);
            else {
                fprintf(stderr,