Clean environment variables for pacstrap

Makefile

@@ -4,7 +4,7 @@ DOCKER_IMAGE:=base
 
 rootfs:
 	$(eval TMPDIR := $(shell mktemp -d))
-	pacstrap -C /usr/share/devtools/pacman-extra.conf -c -d -G -M $(TMPDIR) $(shell cat packages)
+	env -i pacstrap -C /usr/share/devtools/pacman-extra.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