include config.h in all sources

After we've been hit by Large File Support problems several times in
the past week (which only occur on 32 bit platforms, which I don't
have), this is yet another attempt to fix the issue.

src/cue/cue_tag.c

@@ -1,3 +1,4 @@
+#include "config.h"
 #include "cue_tag.h"
 
 static struct tag*

src/cue/cue_tag.h

@@ -1,12 +1,13 @@
 #ifndef MPD_CUE_TAG_H
 #define MPD_CUE_TAG_H
 
-#include "config.h"
+#include "check.h"
 
 #ifdef HAVE_CUE /* libcue */
 
+#include "tag.h"
+
 #include <libcue/libcue.h>
-#include "../tag.h"
 
 struct tag*
 cue_tag_file(	FILE*,