respect proxy in sudo commands

this makes pacman over tor work!
systemd unit to launch dhcpd4 on an interface
[integrity] check for almost-full filesystems
fix emacs-php-mode regex

https://bugs.archlinux.org/task/41825
https://projects.archlinux.org/svntogit/community.git/commit/trunk?h=packages/emacs-php-mode&id=e9a6ec824bce512ed580ba4600534abe0bce6384