diff --git a/cc/gen.go b/cc/gen.go
index edae061..6f9036b 100644
--- a/cc/gen.go
+++ b/cc/gen.go
@@ -24,6 +24,8 @@
 )
 
 func init() {
+	pctx.SourcePathVariable("m4Cmd", "prebuilts/build-tools/${config.HostPrebuiltTag}/bin/m4")
+
 	pctx.HostBinToolVariable("aidlCmd", "aidl-cpp")
 	pctx.HostBinToolVariable("syspropCmd", "sysprop_cpp")
 }