Support file formats that do not support multi-line comments

file.go

@@ -87,7 +87,7 @@ scannerloop:
 				if strings.HasPrefix(line, singleComment) {
 					// check if single comment is a prefix of multi comment
 					for _, ml := range language.multiLines {
-						if strings.HasPrefix(line, ml[0]) {
+						if ml[0] != "" && strings.HasPrefix(line, ml[0]) {
 							break singleloop
 						}
 					}
@@ -109,6 +109,10 @@ scannerloop:
 
 		isCode := false
 		lenLine := len(line)
+		if len(language.multiLines) == 1 && len(language.multiLines[0]) == 2 && language.multiLines[0][0] == "" {
+			onCode(clocFile, opts, len(inComments) > 0, line, lineOrg)
+			continue
+		}
 		for pos := 0; pos < lenLine; {
 			for _, ml := range language.multiLines {
 				begin, end := ml[0], ml[1]

file_test.go

@@ -309,6 +309,52 @@ func TestAnalyzeFile4JavaWithCommentInCodeLine(t *testing.T) {
 	}
 }
 
+func TestAnalyzeFile4Makefile(t *testing.T) {
+	tmpfile, err := ioutil.TempFile("", "Makefile.am")
+	if err != nil {
+		t.Logf("ioutil.TempFile() error. err=[%v]", err)
+		return
+	}
+	defer os.Remove(tmpfile.Name())
+
+	tmpfile.Write([]byte(`# This is a simple Makefile with comments
+	.PHONY: test build
+
+	build:
+		mkdir -p bin
+		GO111MODULE=on go build -o ./bin/gocloc cmd/gocloc/main.go
+
+	# Another comment
+	update-package:
+		GO111MODULE=on go get -u github.com/hhatto/gocloc
+
+	run-example:
+		GO111MODULE=on go run examples/languages.go
+		GO111MODULE=on go run examples/files.go
+
+	test:
+		GO111MODULE=on go test -v
+`))
+
+	language := NewLanguage("Makefile", []string{"#"}, [][]string{{"", ""}})
+	clocOpts := NewClocOptions()
+	clocFile := AnalyzeFile(tmpfile.Name(), language, clocOpts)
+	tmpfile.Close()
+
+	if clocFile.Blanks != 4 {
+		t.Errorf("invalid logic. blanks=%v", clocFile.Blanks)
+	}
+	if clocFile.Comments != 2 {
+		t.Errorf("invalid logic. comments=%v", clocFile.Comments)
+	}
+	if clocFile.Code != 11 {
+		t.Errorf("invalid logic. code=%v", clocFile.Code)
+	}
+	if clocFile.Lang != "Makefile" {
+		t.Errorf("invalid logic. lang=%v", clocFile.Lang)
+	}
+}
+
 func TestAnalayzeReader(t *testing.T) {
 	buf := bytes.NewBuffer([]byte(`#!/bin/python