diff --git a/tests/Makefile.in b/tests/Makefile.in
index 2bfb20e..17232e7 100644
--- a/tests/Makefile.in
+++ b/tests/Makefile.in
@@ -62,6 +62,8 @@
 CCDEPMODE = @CCDEPMODE@
 CFLAGS = @CFLAGS@
 CONFIGURE_DEPENDS = @CONFIGURE_DEPENDS@
+CPLUSPLUS_FOUND_FALSE = @CPLUSPLUS_FOUND_FALSE@
+CPLUSPLUS_FOUND_TRUE = @CPLUSPLUS_FOUND_TRUE@
 CPP = @CPP@
 CPPFLAGS = @CPPFLAGS@
 CXX = @CXX@