write-or-die.h: move declarations for write-or-die.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/pkt-line.c b/pkt-line.c
index 30469eb..36ae0fe 100644
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -4,6 +4,7 @@
 #include "hex.h"
 #include "run-command.h"
 #include "wrapper.h"
+#include "write-or-die.h"
 
 char packet_buffer[LARGE_PACKET_MAX];
 static const char *packet_trace_prefix = "git";