cmake now includes `FindIconv`. Rename ours to avoid any confusion.

actions: set permissions

Several compatibility fixes

We now allow leading and trailing dots in username and email addresses.
Test that we do so.

clone: don't mix up "http://url" with "http:/url" when figuring out if we should do a local clone

process: test /usr/bin/false on BSDs

Support setting oid type for in-memory repositories

Pass a pointer to the quote counts so that we can increment it.

Ensure that we declare variables at the top of the block for broad
compatibility with old compilers.

push: set generic error in push_negotiation cb

release: add a compatibility label

Add a compatibility label to the release.yml to describe things that are for improved cross-platform compatibility.

When a user returns `-1` in a `push_negotiation` callback, we set the
error to whatever's hanging out in the buffer, probably something about
a missing configuration entry.

Clear the error buffer before invoking the callback, so that if a user
does not set an error message in their callback that we can detect. If
there is no error but `-1` is returned, set a generic error message.

fetch: enable deepening/shortening shallow clones

util: suppress some uninitialized variable warnings

Avoid macro redefinition of ENABLE_INTSAFE_SIGNED_FUNCTIONS

git2: Fix crash when called w/o parameters

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

Our process tests were previously testing that false is
`/bin/false` everywhere except macOS, where it exists as
`/usr/bin/false`. . Extend this to all BSDs.

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

ci: overwrite nonsense in /usr/local during macOS setup

GitHub Actions has borked their homebrew setup by first `brew
installing` things into `/usr/local` _and then_ putting their
own things in their place (eg `python`).

This breaks Homebrew, since it thinks it has `python` installed, but
it's actually something else.

Try to avoid using things that are in this bad state.

https://github.com/orgs/community/discussions/78266

A shallow repository can currently only be completely unshallowed, which
is caused by mark_local() only marking locally-existing objects as
wanted if the fetch depth is set to INT_MAX (GIT_FETCH_DEPTH_UNSHALLOW).
This prevents deepening the history of a shallow clone to an arbitrary
number of commits, which may be preferable over full unshallowing for
large repositories.

Enable deepening and shortening shallow clones by marking
locally-existing objects as wanted whenever the fetch depth is set to
any non-default value (either GIT_FETCH_DEPTH_UNSHALLOW or an arbitrary
positive integer).

In C99 functions need to be declared before they are defined.
We could just add the declarations before them, but including the
header allows the compiler to warn if they differ.