diff --git a/js/src/config/recurse.mk b/js/src/config/recurse.mk
index b5f5fdd6499..6f11db39cc9 100644
--- a/js/src/config/recurse.mk
+++ b/js/src/config/recurse.mk
@@ -22,7 +22,8 @@ endif
 #   make -C foo/baz
 #   make -C qux
 
-ifeq (1_.,$(MOZ_PSEUDO_DERECURSE)_$(DEPTH))
+# MOZ_PSEUDO_DERECURSE can have values other than 1.
+ifeq (1_.,$(if $(MOZ_PSEUDO_DERECURSE),1)_$(DEPTH))
 
 include root.mk