Support "**" wildcard in .gitignore and .gitattributes

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t3001-ls-files-others-exclude.sh b/t/t3001-ls-files-others-exclude.sh
index dc2f045..efb7ebc 100755
--- a/t/t3001-ls-files-others-exclude.sh
+++ b/t/t3001-ls-files-others-exclude.sh
@@ -220,4 +220,22 @@
 	test_cmp expect actual
 '
 
+test_expect_success 'ls-files with "**" patterns' '
+	cat <<\EOF >expect &&
+a.1
+one/a.1
+one/two/a.1
+three/a.1
+EOF
+	git ls-files -o -i --exclude "**/a.1" >actual
+	test_cmp expect actual
+'
+
+
+test_expect_success 'ls-files with "**" patterns and no slashes' '
+	: >expect &&
+	git ls-files -o -i --exclude "one**a.1" >actual &&
+	test_cmp expect actual
+'
+
 test_done