[PATCH 0/6 v3] Allow Git repositories to be shared using POSIX ACLs

This version should include fixes for all of Junio's comment:

[PATCH 1/6] Add a testcase for ACL with restrictive umask.
=> This should pass with any umask, and includes a fix for FreeBSD
(but I'm not sure it's sufficient)

[PATCH 3/6] git_mkstemp_mode, xmkstemp_mode: variants of gitmkstemps with mode argument.
=> better log message suggested by Junio.

[PATCH 5/6] git_mkstemps_mode: don't set errno to EINVAL on exit.
=> I actually got rid of this return EINVAL.