[monitoring-plugins] check_curl: make -C obvious (from check_http, ...

[Andreas Baumann]

 Module: monitoring-plugins
 Branch: feature_check_curl
 Commit: 1debd29b573f4d81eeba4d7f78f797c348b231ce
 Author: Andreas Baumann <mail at andreasbaumann.cc>
   Date: Thu Apr  8 15:14:53 2021 +0200
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=1debd29

check_curl: make -C obvious (from check_http, part 2)

---

 plugins/check_curl.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/plugins/check_curl.c b/plugins/check_curl.c
index 892300a..8fc97f4 100644
--- a/plugins/check_curl.c
+++ b/plugins/check_curl.c
@@ -1858,6 +1858,10 @@ print_usage (void)
   printf (" %s -H <vhost> | -I <IP-address> -C <warn_age>[,<crit_age>]\n",progname);
   printf ("       [-p <port>] [-t <timeout>] [-4|-6] [--sni]\n");
   printf ("\n");
+#ifdef LIBCURL_FEATURE_SSL
+  printf ("%s\n", _("In the first form, make an HTTP request."));
+  printf ("%s\n\n", _("In the second form, connect to the server and check the TLS certificate."));
+#endif
   printf ("%s\n", _("WARNING: check_curl is experimental. Please use"));
   printf ("%s\n\n", _("check_http if you need a stable version."));
 }