Index: configure.ac
===================================================================
--- configure.ac	(revision 4ae78c10a7d9e92dd079b2693e1de5ac44e5f368)
+++ configure.ac	(revision 969e7ee704dd26b9eacb5486aaec9fac43861ca5)
@@ -28,12 +28,14 @@
 # New AST toggling support
 AH_TEMPLATE([CFA_USE_NEW_AST],[Sets whether or not to use the new-ast, this is adefault value and can be overrided by --old-ast and --new-ast])
+DEFAULT_NEW_AST="False"
 AC_ARG_ENABLE(new-ast,
 	[  --enable-new-ast     whether or not to use new ast as the default AST algorithm],
 	[case "${enableval}" in
-		yes) newast=true ;;
-		no)  newast=false ;;
+		yes) newast=true ; DEFAULT_NEW_AST="True"  ;;
+		no)  newast=false; DEFAULT_NEW_AST="False" ;;
 		*) AC_MSG_ERROR([bad value ${enableval} for --enable-new-ast]) ;;
 	esac],[newast=false])
 AC_DEFINE_UNQUOTED([CFA_USE_NEW_AST], $newast)
+AC_SUBST(DEFAULT_NEW_AST)
 
 #==============================================================================
Index: tests/config.py.in
===================================================================
--- tests/config.py.in	(revision 4ae78c10a7d9e92dd079b2693e1de5ac44e5f368)
+++ tests/config.py.in	(revision 969e7ee704dd26b9eacb5486aaec9fac43861ca5)
@@ -9,2 +9,3 @@
 HOSTARCH = "@host_cpu@"
 DISTRIBUTE = @HAS_DISTCC@
+NEWAST = @DEFAULT_NEW_AST@