Instaweb would not properly rebuild if the build-time
parameters changed. Fix this by depending on the
GIT-SCRIPT-DEFINES meta-file and using $(cmd_munge_script)
like all the other shell scripts. This requires adding a few
new parametres to cmd_munge_script, but that doesn't hurt
existing scripts.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>