parsing: add timezone to ident structures

This will allow us to mimic Git's behaviour of showing times in the
originator's timezone when displaying commits and tags.

Signed-off-by: John Keeping <john@keeping.me.uk>
diff --git a/cgit.h b/cgit.h
index de5c94a..501cb48 100644
--- a/cgit.h
+++ b/cgit.h
@@ -130,9 +130,11 @@
 	char *author;
 	char *author_email;
 	unsigned long author_date;
+	int author_tz;
 	char *committer;
 	char *committer_email;
 	unsigned long committer_date;
+	int committer_tz;
 	char *subject;
 	char *msg;
 	char *msg_encoding;
@@ -142,6 +144,7 @@
 	char *tagger;
 	char *tagger_email;
 	unsigned long tagger_date;
+	int tagger_tz;
 	char *msg;
 };
 
diff --git a/parsing.c b/parsing.c
index 5283e58..9dacb16 100644
--- a/parsing.c
+++ b/parsing.c
@@ -69,7 +69,7 @@
 	return buf;
 }
 
-static void parse_user(const char *t, char **name, char **email, unsigned long *date)
+static void parse_user(const char *t, char **name, char **email, unsigned long *date, int *tz)
 {
 	struct ident_split ident;
 	unsigned email_len;
@@ -83,6 +83,8 @@
 
 		if (ident.date_begin)
 			*date = strtoul(ident.date_begin, NULL, 10);
+		if (ident.tz_begin)
+			*tz = atoi(ident.tz_begin);
 	}
 }
 
@@ -147,13 +149,13 @@
 
 	if (p && skip_prefix(p, "author ", &p)) {
 		parse_user(p, &ret->author, &ret->author_email,
-			&ret->author_date);
+			&ret->author_date, &ret->author_tz);
 		p = next_header_line(p);
 	}
 
 	if (p && skip_prefix(p, "committer ", &p)) {
 		parse_user(p, &ret->committer, &ret->committer_email,
-			&ret->committer_date);
+			&ret->committer_date, &ret->committer_tz);
 		p = next_header_line(p);
 	}
 
@@ -208,7 +210,7 @@
 	for (p = data; !end_of_header(p); p = next_header_line(p)) {
 		if (skip_prefix(p, "tagger ", &p)) {
 			parse_user(p, &ret->tagger, &ret->tagger_email,
-				&ret->tagger_date);
+				&ret->tagger_date, &ret->tagger_tz);
 		}
 	}