diff --git a/mozilla/config/config.mk b/mozilla/config/config.mk
index 0408abac1c1..e61f8ddd826 100644
--- a/mozilla/config/config.mk
+++ b/mozilla/config/config.mk
@@ -435,6 +435,13 @@ endif
 # we link statically or dynamic?  Assuming dynamic for now.
 LIBS_DIR = -L$(DIST)/bin
 
+#
+# Turn on C++ linking if we have any .cpp files
+#
+ifdef CPPSRCS
+CPP_PROG_LINK = 1
+endif
+
 # all public include files go in subdirectories of PUBLIC:
 PUBLIC		= $(XPDIST)/public