Add parameter to adjust max message length in log listings

The parameter "max-message-length" can be specified in cgitrc, default value
is 60.

This affects the log message shown in repo summary and shortlog.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/ui-summary.c b/ui-summary.c
index 04d4912..5518d01 100644
--- a/ui-summary.c
+++ b/ui-summary.c
@@ -33,7 +33,7 @@
 		url = cgit_pageurl(cgit_query_repo, "commit", 
 				   fmt("id=%s", sha1_to_hex(sha1)));
 		html_link_open(url, NULL, NULL);
-		html_ntxt(80, info->subject);
+		html_ntxt(cgit_max_msg_len, info->subject);
 		html_link_close();
 		html("</td></tr>\n");
 		cgit_free_commitinfo(info);