Merge a handful of topics from the 'master' front

As the 'master' front will soon tag a preview and then release
candidates for 2.38, it is unknown if we are going to issue another
maintenance release on the 2.37.x track, but as we have accumulated
enough material there, let's prepare a draft for it.

Even if we end up not tagging 2.37.4, it would help motivated distro
packagers to maintain their slightly older and "more stable" versions.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/RelNotes/2.37.4.txt

@@ -0,0 +1,31 @@
+Git 2.37.4 Release Notes
+========================
+
+This primarily is to backport various fixes accumulated on the 'master'
+front since 2.37.3.
+
+Fixes since v2.37.3
+-------------------
+
+ * An earlier optimization discarded a tree-object buffer that is
+   still in use, which has been corrected.
+
+ * Fix deadlocks between main Git process and subprocess spawned via
+   the pipe_command() API, that can kill "git add -p" that was
+   reimplemented in C recently.
+
+ * xcalloc(), imitating calloc(), takes "number of elements of the
+   array", and "size of a single element", in this order.  A call that
+   does not follow this ordering has been corrected.
+
+ * The preload-index codepath made copies of pathspec to give to
+   multiple threads, which were left leaked.
+
+ * Update the version of Ubuntu used for GitHub Actions CI from 18.04
+   to 22.04.
+
+ * The auto-stashed local changes created by "git merge --autostash"
+   was mixed into a conflicted state left in the working tree, which
+   has been corrected.
+
+Also contains other minor documentation updates and code clean-ups.

RelNotes

@@ -1 +1 @@
-Documentation/RelNotes/2.37.3.txt
+Documentation/RelNotes/2.37.4.txt