This utility needs File::FcntlLock which Gentoo doesn't package

--- a/OS/Makefile-Base
+++ b/OS/Makefile-Base
@@ -253,7 +253,7 @@
         transport-filter.pl convert4r3 convert4r4 \
         exim_checkaccess \
         exim_dbmbuild exim_dumpdb exim_fixdb exim_tidydb \
-	exim_lock exim_msgdate exim_id_update
+	exim_lock exim_msgdate
 
 
 # Targets for special-purpose configuration header builders