Add support for ** matches in ignores

This is an experimental addition to add ** support to fnmatch
pattern matching in libgit2.  It needs more testing.

src/fnmatch.c

@@ -30,6 +30,7 @@ p_fnmatchx(const char *pattern, const char *string, int flags, size_t recurs)
 		const char *stringstart;
 		char *newp;
 		char c, test;
+		int recurs_flags = flags & ~FNM_PERIOD;
 
 		if (recurs-- == 0)
 				return FNM_NORES;
@@ -53,9 +54,13 @@ p_fnmatchx(const char *pattern, const char *string, int flags, size_t recurs)
 						break;
 				case '*':
 						c = *pattern;
-						/* Collapse multiple stars. */
-						while (c == '*')
+
+						/* Apply '**' to overwrite PATHNAME match */
+						if (c == '*') {
+							flags &= ~FNM_PATHNAME;
+							while (c == '*')
 								c = *++pattern;
+						}
 
 						if (*string == '.' && (flags & FNM_PERIOD) &&
 							(string == stringstart ||
@@ -80,7 +85,7 @@ p_fnmatchx(const char *pattern, const char *string, int flags, size_t recurs)
 						while ((test = *string) != EOS) {
 								int e;
 
-								e = p_fnmatchx(pattern, string, flags & ~FNM_PERIOD, recurs);
+								e = p_fnmatchx(pattern, string, recurs_flags, recurs);
 								if (e != FNM_NOMATCH)
 										return e;
 								if (test == '/' && (flags & FNM_PATHNAME))

tests/attr/ignore.c

@@ -54,6 +54,19 @@ void test_attr_ignore__ignore_root(void)
 	assert_is_ignored(true, "NewFolder/NewFolder/File.txt");
 }
 
+void test_attr_ignore__full_paths(void)
+{
+	cl_git_rewritefile("attr/.gitignore", "Folder/*/Contained");
+
+	assert_is_ignored(true, "Folder/Middle/Contained");
+	assert_is_ignored(false, "Folder/Middle/More/More/Contained");
+
+	cl_git_rewritefile("attr/.gitignore", "Folder/**/Contained");
+
+	assert_is_ignored(true, "Folder/Middle/Contained");
+	assert_is_ignored(true, "Folder/Middle/More/More/Contained");
+}
+
 
 void test_attr_ignore__skip_gitignore_directory(void)
 {