xlsh-without-x: Tweak PKGBUILD and add some patches

Refresh things a bit in the PKGBUILD, I've now forked xlsh and maintain my
changes in a git repo; so we'll use the patches from there instead of one big
"patch" file.

Also adding patches that:
- don't block signals, as this caused issues (e.g. w/ systemd on shutdown)
- set up environment from PAM, so we get variables set from pam_env or logind
glib2-jjk: upgrade to 2.42.1
mesa-jjk: upgrade to 10.3.4