Commit Briefs
make `serve-gemini' use gemexp (from repo) instead of gmid
the standalone / config-less mode was removed from gmid and put into gemexp time ago...
remove explicit #include endian.h
unfortunately that's not portable. config.h will include the right stuff however.
disable -Werror=use-after free for CI
gcc' use after free detection is busted and sees one in vis.c where it's not possible.