Add PKGBUILD
Fix #1: Fix 32-bit compilation

Fix a few instances of 'error: cast from pointer to integer of different size'
(and the inverse) on 32-bit compilation by using correct casting.
Fix #2: Bash-ism

Fixed by requiring bash, not /bin/sh.
Merge remote-tracking branch 'origin/master' into guns

* origin/master:
  Fix #2: Bash-ism
  Fix #1: Fix 32-bit compilation