--- ac-tools/Make.conf.in.orig
+++ ac-tools/Make.conf.in
@@ -87,6 +87,7 @@
 # BSD install
 INSTALL=@INSTALL@
 INSTALL_PROGRAM=@INSTALL_PROGRAM@
+INSTALL_SCRIPT=@INSTALL_SCRIPT@
 INSTALL_DATA=@INSTALL_DATA@
 MKINSTALLDIRS=@MKINSTALLDIRS@
 
