diff --git a/src/config.mk.in b/src/config.mk.in
index 1b5175b..f55bea6 100644
--- a/src/config.mk.in
+++ b/src/config.mk.in
@@ -169,6 +169,10 @@
 MSGFMT		= @MSGFMT@
 MSGFMT_DESKTOP	= @MSGFMT_DESKTOP@
 
+### set if $SOURCE_DATE_EPOCH was set when running configure
+BUILD_DATE_MSG	= @BUILD_DATE_MSG@
+
+
 # Make sure that "make first" will run "make all" once configure has done its
 # work.  This is needed when using the Makefile in the top directory.
 first: all