rewrite Makefile, use git archive

.gitignore

@@ -1,3 +1 @@
-/genkernel.8
-/genkernel-*.tar.bz2
-/ChangeLog
+/*.tar.*

Makefile

@@ -1,16 +1,13 @@
-PACKAGE_VERSION = `/bin/fgrep GK_V= genkernel | sed "s/.*GK_V='\([^']\+\)'/\1/"`
-distdir = genkernel-$(PACKAGE_VERSION)
+VERSION ?= 
+distdir = genkernel-$(VERSION)
 
 # Add off-Git/generated files here that need to be shipped with releases
-EXTRA_DIST = genkernel.8 ChangeLog
+EXTRA_DIST = genkernel.8
 
 genkernel.8: doc/genkernel.8.txt doc/asciidoc.conf Makefile genkernel
-	a2x --conf-file=doc/asciidoc.conf --attribute="genkernelversion=$(PACKAGE_VERSION)" \
+	a2x --conf-file=doc/asciidoc.conf --attribute="genkernelversion=$(VERSION)" \
 		 --format=manpage -D . "$<"
 
-ChangeLog:
-	git log >$@
-
 clean:
 	rm -f $(EXTRA_DIST)
 
@@ -19,12 +16,9 @@ check-git-repository:
 	git diff --cached --quiet || { echo 'STOP, you have uncommitted changes in the index' ; false ; }
 
 dist: check-git-repository $(EXTRA_DIST)
-	rm -Rf "$(distdir)" "$(distdir)".tar "$(distdir)".tar.bz2
-	mkdir "$(distdir)"
-	git ls-files -z | xargs -0 cp --no-dereference --parents --target-directory="$(distdir)" \
-		$(EXTRA_DIST)
-	tar cf "$(distdir)".tar "$(distdir)"
-	bzip2 -9v "$(distdir)".tar
-	rm -Rf "$(distdir)"
+	test -n "$(VERSION)" || { echo "VERSION not set" >&2; exit 1; }
+	git archive --prefix=$(distdir)/ --format=tar "v$(VERSION)" > $(distdir).tar
+	rm -f $(distdir).tar.xz
+	xz $(distdir).tar
 
 .PHONY: clean check-git-repository dist