+btree.html: btree.but
+ halibut --html=$@ $<
+
+# Ensure tweak.h reflects this version number, and then run a
+# command like `make release VERSION=3.00'.
+release: tweak.1 btree.html
+ mkdir -p reltmp/tweak-$(VERSION)
+ for i in *.c *.h *.but tweak.1 btree.html Makefile; do \
+ ln -s ../../$$i reltmp/tweak-$(VERSION); \
+ done
+ (cd reltmp; tar chzvf ../tweak-$(VERSION).tar.gz tweak-$(VERSION))
+ rm -rf reltmp
+