[monitoring-plugins] Add snippet/c++defs from gnulib

[RincewindsHat]

 Module: monitoring-plugins
 Branch: update_gnulib_2021
 Commit: 7889cf231d69bdd7350ab268d610646f2df8560f
 Author: RincewindsHat <12514511+RincewindsHat at users.noreply.github.com>
   Date: Tue Aug 23 18:43:54 2022 +0200
    URL: https://www.monitoring-plugins.org/repositories/monitoring-plugins/commit/?id=7889cf2

Add snippet/c++defs from gnulib

---

 gl/Makefile.am | 1 +
 1 file changed, 1 insertion(+)

diff --git a/gl/Makefile.am b/gl/Makefile.am
index deb665c..db9348e 100644
--- a/gl/Makefile.am
+++ b/gl/Makefile.am
@@ -48,6 +48,7 @@
 #  mountlist \
 #  regex \
 #  setenv \
+#  snippet/c++defs \
 #  strcase \
 #  strcasestr \
 #  strsep \