Support .rs and .fs files in cc_* module srcs lists

Translate .rs and .fs files to .cpp files using llvm-rs-cc.

Test: builds
Change-Id: I242cea0d09c9985730a512cec7705c3f1479f4ed

cc/makevars.go

@@ -77,6 +77,8 @@ func makeVarsProvider(ctx android.MakeVarsContext) {
 
 	ctx.Strict("AIDL_CPP", "${aidlCmd}")
 
+	ctx.Strict("RS_GLOBAL_INCLUDES", "${config.RsGlobalIncludes}")
+
 	includeFlags, err := ctx.Eval("${config.CommonGlobalIncludes}")
 	if err != nil {
 		panic(err)