diff --git a/tools/build/mk/OptionalObsoleteFiles.inc b/tools/build/mk/OptionalObsoleteFiles.inc
index 026e7e514658..8295ebc0bf57 100644
--- a/tools/build/mk/OptionalObsoleteFiles.inc
+++ b/tools/build/mk/OptionalObsoleteFiles.inc
@@ -894,6 +894,10 @@ OLD_FILES+=usr/share/man/man5/hesiod.conf.5.gz
 # to be filled in
 #.endif
 
+.if ${MK_IDEA} == no
+OLD_FILES+=usr/include/openssl/idea.h
+.endif
+
 .if ${MK_INET6} == no
 OLD_FILES+=rescue/ping6
 OLD_FILES+=sbin/ping6