Handle Win32 shares

#6491: Sets oid_type on repos open with git_repository_open_bare

Git for Windows does some truly bizarre things with
paths that start with a forward slash; and expects you
to escape that with `%(prefix)`. This syntax generally
means to add the prefix that Git was installed to -- eg
`/usr/local` -- unless it's an absolute path, in which
case the leading `%(prefix)/` is just removed. And Git
for Windows expects you to use this syntax for absolute
Unix-style paths (in "Git Bash" or Windows Subsystem for
Linux).

Worse, the behavior used to be that a leading `/` was
not absolute. It would indicate that Git for Windows
should add the prefix. So `//` is required for absolute
Unix-style paths. Yes, this is truly horrifying.

Emulate that behavior, I guess, but only for absolute
paths. We won't deal with the Git install prefix. Also,
give WSL users an escape hatch where they don't have to
think about this and can use the literal path that the
filesystem APIs provide (`//wsl.localhost/...`).

With some paths on Win32, we cannot identify the owner because it's on a
file share (WSL2 or UNC). In that case, don't fail, but identify that
the current user does not own the path. This matches Git for Windows
behavior.

stash: update strarray usage

stash: partial stash specific files

`git_strarray_copy` is deprecated (and has been included in
`deprecated.h` for some time). It should not have remained in
the public `strarray.h`. Remove it.

Fix some warnings in main

clone: clean up options on failure

SHA256: more SHA256 support

Support the notion of a home directory separately from global configuration directory

 Define correct off64_t for AIX

#6422: handle dangling symbolic refs gracefully

Fixes issue #6156.

Signed-off-by: Sven Strickroth <email@cs-ware.de>

Fix build failure with -DEMBED_SSH_PATH

diff_file: Fix crash when freeing a patch representing an empty untracked file

Support OpenSSL 3 in dynamic loading mode

Add new PHP bindings project to language bindings section of README.md

Updates the README.md language binding section to reference a new
project providing PHP bindings at https://github.com/RogerGee/php-git2.

This prevents GIT_MMAP_VALIDATE from failing.
This also prevents git_diff_file_content__unload from attempting to free git_str__initstr.

The git included with xenial is ancient, and lacks sha256 support.

The longest path within a git repository is now a SHA256 format
packfile. Adjust our max length checking to match.