- The fetch phase *must* run after installing pkg dependencies,
otherwise it could fail if we need them for fetching.
- Performance improvements for xbps-src. Only source shutils files
at the start, not every time we use a function.
- Remove buildvars_funcs.sh, its code has been moved into set_tmpl_common_vars().
- Move stripping code into its own file, and don't run it via fakeroot.
- Remove unnecesary reset_tmpl_vars() call in install_pkg().
- Misc changes.