[RFC PATCH v2 0/2] Two new remote helpers

The first helper (fd) is meant for frontends that want to override
how transport link is created. Currently this would require hacks based
on either GIT_SSH or GIT_PROXY (see tortoiseplink). It works by reflecting
the smart transport stream to specified file descriptors.

The second one (ext) invokes specified command, reading/writing smart
transport stream (with optional git://-style request) to its stdin/stdout.
It is meant for situations where one wants unusual kind of transport link.
It can be ssh connection with one-off parameters[1], things like rsh (if
you have to use it because some absolutely incomprehensible reason,
hopefully its really krb5-rsh)[2], wrapping git:// in TLS[3], accessing
servers on unix domain sockets[4], etc...

Changes from last time:
- This cover letter.
- Support \G and \V which are for sending git:// style request in-channel.[5]

[1] "ext::ssh -i somekey user@host.example \S /path/to/repo.git"
[2] "ext::rsh -l user host.example \S /path/to/repo.git"
[3] Don't ask me how, especially not how to get connection to git-daemon2
that way.
[4] "ext::socat - ABSTRACT-CONNECT:/tmp/gits \G/gitolite-admin"
[5] "ext::nc host.example 9418 \G/repo.git \Vfoo.host.example" (with vhost)
or "ext::nc host.example 9418 \G/repo.git" (without vhost).

Ilari Liusvaara (2):
  New remote helper git-remote-fd
  New remote helper: git-remote-ext

 Makefile             |    2 +
 builtin.h            |    2 +
 builtin/remote-ext.c |  300 ++++++++++++++++++++++++++++++++++++++++++++++++++
 builtin/remote-fd.c  |   88 +++++++++++++++
 git.c                |    2 +
 transport-helper.c   |  130 ++++++++++++++++++++++
 transport.h          |    1 +
 7 files changed, 525 insertions(+), 0 deletions(-)
 create mode 100644 builtin/remote-ext.c
 create mode 100644 builtin/remote-fd.c