gc does not clean up after itself when not enough disk space

When git gc fails on no more disk space, it leaves tmp_pack files lying 
around that consume whatever space was available (and fill up the disk 
to 100%). Shouldn't git be deleting these files?

Running git 1.7.9 on cygwin:
# git --version
git version 1.7.9
# uname -a
CYGWIN_NT-6.1-WOW64 ---- 1.7.17(0.262/5/3) 2012-10-19 14:39 i686 Cygwin


Example failure output:

# git gc
Counting objects: 44626, done.
Delta compression using up to 8 threads.
Compressing objects: 100% (7756/7756), done.
fatal: sha1 file '.git/objects/pack/tmp_pack_uJ0E5b' write error: No 
space left on device
error: failed to run repack


Thanks!
Noam