[cache] Tweak headers.

* src/cache/ftccback.h: Include less and move `ftc_node_destroy`...
* src/cache/ftccache.h: ... to here.
* src/cache/ftcmanag.c: Include less.

src/cache/ftccache.h

@@ -87,6 +87,10 @@ FT_BEGIN_HEADER
         ftc_get_top_node_for_hash( ( cache ), ( hash ) )
 #endif
 
+  FT_LOCAL( void )
+  ftc_node_destroy( FTC_Node     node,
+                    FTC_Manager  manager );
+
 
   /*************************************************************************/
   /*************************************************************************/

src/cache/ftccback.h

@@ -19,11 +19,7 @@
 #define FTCCBACK_H_
 
 #include <freetype/ftcache.h>
-#include "ftcmru.h"
-#include "ftcimage.h"
-#include "ftcmanag.h"
-#include "ftcglyph.h"
-#include "ftcsbits.h"
+#include "ftccache.h"
 
 FT_BEGIN_HEADER
 
@@ -81,10 +77,6 @@ FT_BEGIN_HEADER
   FT_LOCAL( void )
   ftc_cache_done( FTC_Cache  cache );
 
-  FT_LOCAL( void )
-  ftc_node_destroy( FTC_Node     node,
-                    FTC_Manager  manager );
-
 FT_END_HEADER
 
 #endif /* FTCCBACK_H_ */

src/cache/ftcmanag.c

@@ -22,7 +22,6 @@
 #include <freetype/internal/ftdebug.h>
 #include <freetype/ftsizes.h>
 
-#include "ftccback.h"
 #include "ftcerror.h"