xbps-src: base-chroot-v2 (reduce artifacts/deps)

This patchset contains multiple changes to xbps-src and
its required package "base-chroot" for building packages
via chroot.

- moved xbps.d(5) conf files to `etc/xbps.d`.
- renamed xbps.d(5) repository files to `etc/xbps.d/repos-{local,remote}*`.
- do not set `--repository` to any xbps command that supports it,
  xbps-src now simply populates `rootdir/etc/xbps.d` with correct
  settings (taking care of CHROOT_READY/IN_CHROOT).
- Unless `-C` is set (to preserve builddir/destdir/autodeps), when
  entering to the chroot (if CHROOT_READY is set), xbps-src will
  clean up the masterdir and then perform a system update to always
  use a constant set of packages for that exact date.
- Improved some normal/error msgs.
- Includes support for `xbps>=0.58`.
- common/hooks: switch to bsdtar.
- base-chroot:
  - base-chroot-musl is gone, now unified for glibc/musl.
  - deps removed: gettext, mpfr, readline, texinfo, which, xz.
  - deps changed: tar -> bsdtar.

Effectively this reduces dependencies in `base-chroot`, makes
it unified for musl and glibc, switches xbps-src to use `bsdtar`
rather than GNU `tar` and `xz`, gets rid of useless host dependencies
like GNU gettext, texinfo, etc.

I've been testing these changes for 1 month or so already,
I was able to build from scratch `base-system` for both native
and multiple targets, i.e `./xbps-src -a target -Nt pkg base-system`

common/hooks/do-fetch/00-distfiles.sh

@@ -50,7 +50,7 @@ contents_cksum() {
 
 	case ${cursufx} in
 	tar|txz|tbz|tlz|tgz|crate)
-		cksum=$($XBPS_DIGEST_CMD <(tar xf "$curfile" --to-stdout))
+		cksum=$($XBPS_DIGEST_CMD <(bsdtar xf "$curfile" --list))
 		if [ $? -ne 0 ]; then
 			msg_error "$pkgver: extracting $curfile to pipe.\n"
 		fi
@@ -95,7 +95,7 @@ contents_cksum() {
 		fi
 		;;
 	gem)
-		cksum=$($XBPS_DIGEST_CMD <(tar -xf "$curfile" data.tar.gz --to-stdout | tar -xzO ))
+		cksum=$($XBPS_DIGEST_CMD <(bsdtar -xf "$curfile" data.tar.gz --list | bsdtar -xzO ))
 		;;
 	*)
 		msg_error "$pkgver: cannot guess $curfile extract suffix. ($cursufx)\n"