index-pack: smarter memory usage when appending objects
index-pack: smarter memory usage when appending objects

In the same spirit as commit 9892bebafe, let's avoid allocating the full
buffer for the deflated data in write_compressed() in order to write it.
Let's deflate and write the data in chunks instead to reduce memory
usage.

Signed-off-by: Nicolas Pitre <d659c10e27d52b00987b65e85d99bce5480adcae@fluxnic.net>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git