When running install.sh, don't prompt, do clobber, and set
sitepassphrase and localpassphrase to none.
--- Makefile.in.orig	2018-03-31 01:05:50.000000000 -0500
+++ Makefile.in	2021-05-09 10:45:03.000000000 -0500
@@ -801,7 +801,7 @@
 	INSTALL_STRIP_FLAG="$(INSTALL_STRIP_FLAG)" \
 	prefix="$(prefix)" sysconfdir="$(sysconfdir)" \
 	path_to_vi="$(path_to_vi)" path_to_sendmail="$(path_to_sendmail)" \
-	$(top_srcdir)/installer/install.sh
+	$(top_srcdir)/installer/install.sh -n -f -s none -l none
 
 uninstall-hook:
 	rm -f ${prefix}/sbin/tripwire $(prefix)/sbin/twadmin $(prefix)/sbin/twprint $(prefix)/sbin/siggen