When portmaster aborts, it should still honor PM_DEL_BUILD_ONLY=pm_dbo

[TheDreamer]

When something goes wrong with portmaster, it doesn't delete the build only ports and they weren't marked as automatic. And, the suggested command to restart, should not include the build only ports.

[TheDreamer]

When portmaster installs the build-only depends (applied patch from issue #34), it does delete them when it aborts. Appears build_deps_il only contains build-only depends that were installed from packages. A bit lost on what goes on for the ones that are built.... build_only_dl_g?