setup.h: move declarations for setup.c functions from cache.h

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/mailmap.c b/mailmap.c
index 2c6e9b2..c24a16e 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -3,6 +3,7 @@
 #include "string-list.h"
 #include "mailmap.h"
 #include "object-store.h"
+#include "setup.h"
 
 #define DEBUG_MAILMAP 0
 #if DEBUG_MAILMAP