* "git clone --reference $there --recurse-submodules $super" has been

taught to guess repositories usable as references for submodules of

$super that are embedded in $there while making a clone of the

superproject borrow objects from $there; extend the mechanism to

also allow submodules of these submodules to borrow repositories

embedded in these clones of the submodules embedded in the clone of

the superproject.

* Unlike "git am --abort", "git cherry-pick --abort" moved HEAD back

to where cherry-pick started while picking multiple changes, when

the cherry-pick stopped to ask for help from the user, and the user

did "git reset --hard" to a different commit in order to re-attempt

the operation.

(merge ce73bb22d8 sb/sequencer-abort-safety later to maint).

* Code cleanup in shallow boundary computation.

(merge 649b0c316a nd/shallow-fixup later to maint).

* A recent update to receive-pack to make it easier to drop garbage

objects made it clear that GIT_ALTERNATE_OBJECT_DIRECTORIES cannot

have a pathname with a colon in it (no surprise!), and this in turn

made it impossible to push into a repository at such a path. This

has been fixed by introducing a quoting mechanism used when

appending such a path to the colon-separated list.

(merge 5e74824fac jk/quote-env-path-list-component later to maint).

* The function usage_msg_opt() has been updated to say "fatal:"

before the custom message programs give, when they want to die

with a message about wrong command line options followed by the

standard usage string.

(merge 87433261a4 jk/parseopt-usage-msg-opt later to maint).

* "git index-pack --stdin" needs an access to an existing repository,

but "git index-pack file.pack" to generate an .idx file that

corresponds to a packfile does not.

(merge 29401e1575 jk/index-pack-wo-repo-from-stdin later to maint).

* Fix for NDEBUG builds.

(merge 08414938a2 jt/mailinfo-fold-in-body-headers later to maint).