merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/Documentation/git-remote-fd.txt

@@ -0,0 +1,59 @@
+git-remote-fd(1)
+================
+
+NAME
+----
+git-remote-fd - Reflect smart transport stream back to caller
+
+SYNOPSIS
+--------
+"fd::<infd>[,<outfd>][/<anything>]" (as URL)
+
+DESCRIPTION
+-----------
+This helper uses specified file descriptors to connect to a remote Git server.
+This is not meant for end users but for programs and scripts calling git
+fetch, push or archive.
+
+If only <infd> is given, it is assumed to be a bidirectional socket connected
+to remote Git server (git-upload-pack, git-receive-pack or
+git-upload-archive). If both <infd> and <outfd> are given, they are assumed
+to be pipes connected to a remote Git server (<infd> being the inbound pipe
+and <outfd> being the outbound pipe.
+
+It is assumed that any handshaking procedures have already been completed
+(such as sending service request for git://) before this helper is started.
+
+<anything> can be any string. It is ignored. It is meant for providing
+information to user in the URL in case that URL is displayed in some
+context.
+
+ENVIRONMENT VARIABLES
+---------------------
+GIT_TRANSLOOP_DEBUG::
+	If set, prints debugging information about various reads/writes.
+
+EXAMPLES
+--------
+`git fetch fd::17 master`::
+	Fetch master, using file descriptor #17 to communicate with
+	git-upload-pack.
+
+`git fetch fd::17/foo master`::
+	Same as above.
+
+`git push fd::7,8 master (as URL)`::
+	Push master, using file descriptor #7 to read data from
+	git-receive-pack and file descriptor #8 to write data to
+	same service.
+
+`git push fd::7,8/bar master`::
+	Same as above.
+
+SEE ALSO
+--------
+linkgit:gitremote-helpers[7]
+
+GIT
+---
+Part of the linkgit:git[1] suite