diff --git a/makefile b/makefile
index dbfd9a7..c7a2eff 100644
--- a/makefile
+++ b/makefile
@@ -21,7 +21,10 @@ test:
 	./gradlew test
 
 $(TARNAME):
-	git ls-files -z | xargs -0 tar -czf $(TARNAME)
+	git archive --format=tar --prefix=$(DIRNAME)/ HEAD > intermediate.tar
+	tar -f intermediate.tar --delete $(DIRNAME)/doc
+	gzip -9 -c intermediate.tar > $(TARNAME)
+	rm intermediate.tar
 
 $(TARNAME).minisig: $(TARNAME)
 	minisign -Sm $(TARNAME)