diff --git a/tools/build/options/makeman b/tools/build/options/makeman
index 0e21499ffd6a..acc0eb52a84b 100755
--- a/tools/build/options/makeman
+++ b/tools/build/options/makeman
@@ -3,7 +3,7 @@
 # This file is in the public domain.
 
 set -o errexit
-LC_ALL=C
+export LC_ALL=C
 
 ident='$FreeBSD$'