Warning cleanup

- ignoring const
- declarations after statements
- some C files didnt include own headers (risking them getting out of sync)

Closes #1064

src/common/dbus/dbus-plugin.c

@@ -26,6 +26,7 @@
 #include <dbus/dbus-glib-lowlevel.h>
 #include <glib/gi18n.h>
 #include "hexchat-plugin.h"
+#include "dbus-plugin.h"
 
 #define PNAME _("remote access")
 #define PDESC _("plugin for remote access using DBUS")

src/common/dbus/example.c

@@ -33,7 +33,7 @@ guint command_id;
 guint server_id;
 
 static void
-write_error (char *message,
+write_error (const char *message,
 	     GError **error)
 {
 	if (error == NULL || *error == NULL) {