pacstrap: set up the image using NoExtract rules to prune dead weight

A docker container does not need tons of locales in order to do its job,
nor does it need extensive (or any) documentation.

With this change, a bare pacstrapped directory drops from 500MB to 390MB

.gitignore

@@ -2,3 +2,4 @@
 *.orig
 /.idea
 /archlinux.tar
+rootfs/etc/pacman.conf

Makefile

@@ -4,7 +4,9 @@ DOCKER_IMAGE:=base
 
 rootfs:
 	$(eval TMPDIR := $(shell mktemp -d))
-	env -i pacstrap -C /usr/share/devtools/pacman-extra.conf -c -d -G -M $(TMPDIR) $(shell cat packages)
+	cp /usr/share/devtools/pacman-extra.conf rootfs/etc/pacman.conf
+	cat pacman-conf.d-noextract.conf >> rootfs/etc/pacman.conf
+	env -i pacstrap -C rootfs/etc/pacman.conf -c -d -G -M $(TMPDIR) $(shell cat packages)
 	cp --recursive --preserve=timestamps --backup --suffix=.pacnew rootfs/* $(TMPDIR)/
 	arch-chroot $(TMPDIR) locale-gen
 	arch-chroot $(TMPDIR) pacman-key --init

pacman-conf.d-noextract.conf

+[options]
+NoExtract  = usr/share/help/* !usr/share/help/en*
+NoExtract  = usr/share/gtk-doc/html/* usr/share/doc/*
+NoExtract  = usr/share/locale/* usr/share/X11/locale/* usr/share/i18n/*
+NoExtract   = !*locale*/en*/* !usr/share/i18n/charmaps/UTF-8.gz !usr/share/*locale*/locale.*
+NoExtract   = !usr/share/*locales/en_?? !usr/share/*locales/i18n* !usr/share/*locales/iso*
+NoExtract   = !usr/share/*locales/trans*
+NoExtract  = usr/share/man/* usr/share/info/*
+NoExtract  = usr/share/vim/vim*/lang/*