repack: move `write_cruft_pack()` out of the builtin

In an identical fashion as the previous commit, move the function
`write_cruft_pack()` into its own compilation unit, and make the
function visible through the repack.h API.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/Makefile b/Makefile
index ba4f3bbfa2..e3c4bf1b4a 100644
--- a/Makefile
+++ b/Makefile
@@ -1137,6 +1137,7 @@ LIB_OBJS += refs/ref-cache.o
 LIB_OBJS += refspec.o
 LIB_OBJS += remote.o
 LIB_OBJS += repack.o
+LIB_OBJS += repack-cruft.o
 LIB_OBJS += repack-filtered.o
 LIB_OBJS += repack-geometry.o
 LIB_OBJS += repack-midx.o