irc: fix extract of channel in parser for JOIN/PART messages when there is a colon before the channel name (closes #83)

The problem was only affecting scripts or triggers using the parser.
The irc plugin does not use the "channel" variable built by the parser
(when parsing JOIN/PART messages).

ChangeLog.asciidoc

@@ -106,6 +106,8 @@ http://weechat.org/files/releasenotes/ReleaseNotes-devel.html[release notes]
 * alias: change default command for alias /beep to "/print -beep"
 * exec: add exec plugin: new command /exec and file exec.conf
 * guile: fix module used after unload of a script
+* irc: fix extract of channel in parser for JOIN/PART messages when there is a
+  colon before the channel name (closes #83)
 * irc: fix duplicate sender name in display of notice (closes #87)
 * irc: fix refresh of buffer name in bar items after join/part/kick/kill
   (closes #86)

src/plugins/irc/irc-message.c

@@ -151,6 +151,12 @@ irc_message_parse (struct t_irc_server *server, const char *message,
             /* now we have: pos --> "#channel :hello!" */
             if (arguments)
                 *arguments = strdup (pos);
+            if ((pos[0] == ':')
+                && ((strncmp (ptr_message, "JOIN ", 5) == 0)
+                    || (strncmp (ptr_message, "PART ", 5) == 0)))
+            {
+                pos++;
+            }
             if (pos[0] != ':')
             {
                 if (irc_channel_is_channel (server, pos))