Mention makewhatis; close #19

Author: jeaye

do_install

@@ -18,4 +18,4 @@ for file in "$tmp_man"/*.3 ; do
   install -m 0644 "$file" "$out";
   gzip -f "$out";
 done
-echo "Done; it's advised to run 'sudo mandb' now."
+echo "Done; it's advised to run 'sudo mandb' (GNU) or 'sudo makewhatis' (BSD) now."