Cirrus-CI: Run makeman script

Run makeman and verify that src.conf.5 has been updated if
required and that there are no missing definition files.

Reviewed by:	emaste
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D39682

.cirrus.yml

@@ -64,6 +64,14 @@ task:
   # Check that includes/Makefile refers to existing directories
   - if ! make -C include/ check-ldirs; then printf "\n>>> include/Makefile lists nonexistant directories <<<\n"; false; fi
 
+  makeman_script:
+  # Check that the committed src.conf.5 matches the one generated by
+  # tools/build/options/makeman (modulo the date which always updates)
+  # XXX: This script is slow so keep it last
+  - (make makeman 2> /tmp/makeman.out); cat /tmp/makeman.out
+  - if ! git diff --exit-code --ignore-matching-lines "^.Dd" share/man/man5/src.conf.5; then printf "\n>>> src.conf.5 was not updated as required <<<\n"; false; fi
+  - if grep -q "no description found" /tmp/makeman.out; then printf "\n>>> Missing description files <<<\n"; false; fi
+
   post_script:
   - df -m
   - du -m -s /usr/obj