diff --git a/mozilla/config/config.mak b/mozilla/config/config.mak
index fd85cc521da..f1126e2c59f 100644
--- a/mozilla/config/config.mak
+++ b/mozilla/config/config.mak
@@ -283,6 +283,13 @@ CFLAGS=$(CFLAGS) -DMOZ_SVG
 CFLAGS=$(CFLAGS) -DMOZ_REFLOW_PERF -DMOZ_REFLOW_PERF_DSP
 !endif
 
+!ifdef MOZ_NEW_CACHE
+CFLAGS=$(CFLAGS) -DMOZ_NEW_CACHE
+!endif
+
+!ifdef USE_IMG2
+CFLAGS=$(CFLAGS) -DUSE_IMG2
+!endif
 
 #//-----------------------------------------------------------------------
 #//