Various distcheck and docs fixes
This fixes #1498 (closed), in the sense that I can no longer reproduce it. Given that the
release rule in
Makefile.am manually deletes the
.deps directories, I suspect this problem is a deep-seated one which people have worked around for a long time. http://gnu-automake.7480.n7.nabble.com/make-distclean-td22165.html seems to do the same.
If #1498 (closed) reoccurs when I do the next 2.58.x release, I’ll a) get quite frustrated; b) potentially reopen it.
This also, mainly, is a load of docs fixes which don’t need backporting to
glib-2-58. I got a bit carried away.
Closes #1498 (closed)