diff --git a/application/palemoon/configure.in b/application/palemoon/configure.in
index df5fb98a13..0dbb0d8bc1 100644
--- a/application/palemoon/configure.in
+++ b/application/palemoon/configure.in
@@ -7,10 +7,10 @@ dnl file, You can obtain one at http://mozilla.org/MPL/2.0/.
 dnl Things we need to carry from confvars.sh
 AC_DEFINE(MOZ_PHOENIX)
 AC_SUBST(MOZ_PHOENIX)
-
 AC_DEFINE(MC_PALEMOON)
 AC_SUBST(MC_PALEMOON)
-
+AC_DEFINE(MOZ_PHOENIX_EXTENSIONS)
+AC_SUBST(MOZ_PHOENIX_EXTENSIONS)
 
 dnl Optional parts of the build.