diff --git a/Makefile.config.in b/Makefile.config.in
index c42a500f..4fd203d2 100644
--- a/Makefile.config.in
+++ b/Makefile.config.in
@@ -55,6 +55,7 @@ ASCIIDOC_FLAGS = --unsafe
 AWK = @AWK@
 CATALOGS = @CATALOGS@
 CC = @CC@
+CXX = @CXX@
 LD = @LD@
 GIT = @GIT@
 CONFDIR = @CONFDIR@