Add --goma flag
diff --git a/eval.go b/eval.go
index 8a521d3..0b620e8 100644
--- a/eval.go
+++ b/eval.go
@@ -332,7 +332,7 @@
 	}
 
 	for _, fn := range files {
-		if ignoreOptionalInclude != "" && ast.op == "-include" && strings.HasPrefix(fn, ignoreOptionalInclude) {
+		if ignoreOptionalInclude != "" && ast.op == "-include" && matchPattern(fn, ignoreOptionalInclude) {
 			continue
 		}
 		c, err := ioutil.ReadFile(fn)
diff --git a/m2n b/m2n
index 3951c3c..80692ba 100755
--- a/m2n
+++ b/m2n
@@ -14,6 +14,7 @@
     cat - <<EOF
 Usage:
   m2n         # for full-build
+  m2n --goma  # use goma. \$HOME/goma must exist
   m2n bionic  # works like mmm
 EOF
     exit 1
@@ -39,6 +40,6 @@
   echo ONE_SHOT_MAKEFILE=${ONE_SHOT_MAKEFILE}
 fi
 
-${kati} --ninja --ignore_optional_include=out/ ${goma_flag}
+${kati} --ninja --ignore_optional_include=out/%.P ${goma_flag}
 
 echo ninja.sh and build.ninja were generated, please run ./ninja.sh