build-vm, tar2fs: get ARCH from command line argument

tar2fs does not run in hasher and without qemu. This causes build
problems for an architecture other than the host.

bin/tar2fs

@@ -35,7 +35,11 @@ EFIPART=
 
 BOOTLOADER="$5"
 
-ARCH="$(arch)"		# NB: sudo => no GLOBAL_ will do either; mind qemu-*
+if [ -n "$6" ]; then
+	ARCH="$6"
+else
+	ARCH="$(arch)"
+fi
 
 case "$ARCH" in
 e2k)

features.in/build-vm/lib/90-build-vm.mk

@@ -45,7 +45,7 @@ tar2fs: check-sudo prepare-tarball-qemu
 	fi; \
 	if ! sudo $$TOPDIR/bin/tar2fs \
 		"$(VM_TARBALL)" "$(VM_RAWDISK)" "$(VM_SIZE)" "$(VM_FSTYPE)" \
-			"$(VM_BOOTLOADER)"; then \
+			"$(VM_BOOTLOADER)" "$(ARCH)"; then \
 		echo "** error: sudo tar2fs failed, see build log" >&2; \
 		exit 1; \
 	fi