repository.h: move declaration of the_index from cache.h

the_index is a global variable defined in repository.c; as such, its
declaration feels better suited living in repository.h rather than
cache.h.  Move it.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -312,10 +312,6 @@ typedef int (*must_prefetch_predicate)(const struct cache_entry *);
 void prefetch_cache_entries(const struct index_state *istate,
 			    must_prefetch_predicate must_prefetch);
 
-#ifdef USE_THE_INDEX_VARIABLE
-extern struct index_state the_index;
-#endif
-
 /* Initialize and use the cache information */
 struct lock_file;
 int do_read_index(struct index_state *istate, const char *path,

repository.h

@@ -170,6 +170,9 @@ struct repository {
 };
 
 extern struct repository *the_repository;
+#ifdef USE_THE_INDEX_VARIABLE
+extern struct index_state the_index;
+#endif
 
 /*
  * Define a custom repository layout. Any field can be NULL, which

t/helper/test-dump-split-index.c

@@ -2,6 +2,7 @@
 #include "test-tool.h"
 #include "cache.h"
 #include "hex.h"
+#include "repository.h"
 #include "setup.h"
 #include "split-index.h"
 #include "ewah/ewok.h"