Clean source files for successfully built packages

[oshazard]

By default apacman will use /tmp (by default a tmpfs on ArchLinux) as a build directory which greatly limits the disk capacity (reliant on RAM capacity) available for building AUR packages.

apacman should automatically clean the build directory for packages that have already been built as it goes, to help reduce the disk usage (or RAM usage in this case). For debugging purposes, packages that have failed to build will be left in the build directory (until reboot).

Additionally, when --nofail flag is used it should clean any package that has failed as well.