core: fix crash on plugin reload when using musl libs (closes #2052)

src/plugins/irc/irc-config.c

@@ -4106,6 +4106,7 @@ void
 irc_config_free ()
 {
     weechat_config_free (irc_config_file);
+    irc_config_file = NULL;
 
     if (irc_config_hook_config_nick_color_options)
     {

src/plugins/irc/irc-list.c

@@ -1340,4 +1340,5 @@ irc_list_end ()
         weechat_hashtable_free (irc_list_filter_hashtable_options);
         irc_list_filter_hashtable_options = NULL;
     }
+    irc_list_hdata_list_channel = NULL;
 }

src/plugins/irc/irc-notify.c

@@ -1307,9 +1307,18 @@ void
 irc_notify_end ()
 {
     if (irc_notify_timer_ison)
+    {
         weechat_unhook (irc_notify_timer_ison);
+        irc_notify_timer_ison = NULL;
+    }
     if (irc_notify_timer_whois)
+    {
         weechat_unhook (irc_notify_timer_whois);
+        irc_notify_timer_whois = NULL;
+    }
     if (irc_notify_hsignal)
+    {
         weechat_unhook (irc_notify_hsignal);
+        irc_notify_hsignal = NULL;
+    }
 }

src/plugins/irc/irc-raw.c

@@ -673,6 +673,11 @@ irc_raw_end ()
 {
     irc_raw_message_free_all ();
 
+    if (irc_raw_buffer)
+    {
+        weechat_buffer_close (irc_raw_buffer);
+        irc_raw_buffer = NULL;
+    }
     if (irc_raw_filter)
     {
         free (irc_raw_filter);

src/plugins/irc/irc.c

@@ -193,6 +193,9 @@ weechat_plugin_init (struct t_weechat_plugin *plugin, int argc, char *argv[])
 
     weechat_plugin = plugin;
 
+    irc_signal_quit_received = 0;
+    irc_signal_upgrade_received = 0;
+
     if (!irc_config_init ())
         return WEECHAT_RC_ERROR;
 
@@ -314,7 +317,10 @@ weechat_plugin_end (struct t_weechat_plugin *plugin)
     (void) plugin;
 
     if (irc_hook_timer)
+    {
         weechat_unhook (irc_hook_timer);
+        irc_hook_timer = NULL;
+    }
 
     if (irc_signal_upgrade_received)
     {