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

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

third_party/git/Documentation/RelNotes/1.8.3.3.txt

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+Git v1.8.3.3 Release Notes
+==========================
+
+Fixes since v1.8.3.2
+--------------------
+
+ * "git apply" parsed patches that add new files, generated by programs
+   other than Git, incorrectly.  This is an old breakage in v1.7.11.
+
+ * Older cURL wanted piece of memory we call it with to be stable, but
+   we updated the auth material after handing it to a call.
+
+ * "git pull" into nothing trashed "local changes" that were in the
+   index.
+
+ * Many "git submodule" operations did not work on a submodule at a
+   path whose name is not in ASCII.
+
+ * "cherry-pick" had a small leak in its error codepath.
+
+ * Logic used by git-send-email to suppress cc mishandled names like
+   "A U. Thor" <author@example.xz>, where the human readable part
+   needs to be quoted (the user input may not have the double quotes
+   around the name, and comparison was done between quoted and
+   unquoted strings).  It also mishandled names that need RFC2047
+   quoting.
+
+ * "gitweb" forgot to clear a global variable $search_regexp upon each
+   request, mistakenly carrying over the previous search to a new one
+   when used as a persistent CGI.
+
+ * The wildmatch engine did not honor WM_CASEFOLD option correctly.
+
+ * "git log -c --follow $path" segfaulted upon hitting the commit that
+   renamed the $path being followed.
+
+ * When a reflog notation is used for implicit "current branch",
+   e.g. "git log @{u}", we did not say which branch and worse said
+   "branch ''" in the error messages.
+
+ * Mac OS X does not like to write(2) more than INT_MAX number of
+   bytes; work it around by chopping write(2) into smaller pieces.
+
+ * Newer MacOS X encourages the programs to compile and link with
+   their CommonCrypto, not with OpenSSL.
+
+Also contains various minor documentation updates.