Rename dirlink to gitlink.

Git changed from dirlink to gitlink in
302b9282c9ddfcc704ca759bdc98c1d5f75eba2f.

Signed-off-by: Jeffrey C. Ollie <jeff@ocjtech.us>
diff --git a/ui-diff.c b/ui-diff.c
index e6b957c..4695e3a 100644
--- a/ui-diff.c
+++ b/ui-diff.c
@@ -37,7 +37,7 @@
 	char *abbrev1, *abbrev2;
 	int subproject;
 
-	subproject = (S_ISDIRLNK(mode1) || S_ISDIRLNK(mode2));
+	subproject = (S_ISGITLINK(mode1) || S_ISGITLINK(mode2));
 	html("<div class='head'>");
 	html("diff --git a/");
 	html_txt(path1);
@@ -78,10 +78,10 @@
 {
 	header(pair->one->sha1, pair->one->path, pair->one->mode,
 	       pair->two->sha1, pair->two->path, pair->two->mode);
-	if (S_ISDIRLNK(pair->one->mode) || S_ISDIRLNK(pair->two->mode)) {
-		if (S_ISDIRLNK(pair->one->mode))
+	if (S_ISGITLINK(pair->one->mode) || S_ISGITLINK(pair->two->mode)) {
+		if (S_ISGITLINK(pair->one->mode))
 			print_line(fmt("-Subproject %s", sha1_to_hex(pair->one->sha1)), 52);
-		if (S_ISDIRLNK(pair->two->mode))
+		if (S_ISGITLINK(pair->two->mode))
 			print_line(fmt("+Subproject %s", sha1_to_hex(pair->two->sha1)), 52);
 		return;
 	}