environment.h: move declarations for environment.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/connect.c b/connect.c
index f3b159b..737dd90 100644
--- a/connect.c
+++ b/connect.c
@@ -1,6 +1,7 @@
 #include "git-compat-util.h"
 #include "cache.h"
 #include "config.h"
+#include "environment.h"
 #include "gettext.h"
 #include "hex.h"
 #include "pkt-line.h"