This is where portable git stores the global configuration which we can
use to adhere to it even though git isn't quite installed on the system.

revwalk: make commit list use 64 bits for time

Preserve modes from a conflict in `git_index_insert`

For most real use cases, repositories with alternates use them as main
object storage. Checking the alternate for objects before the main
repository should result in measurable speedups.

Because of this, we're changing the sorting algorithm to prioritize
alternates *in cases where two backends have the same priority*. This
means that the pack backend for the alternate will be checked before the
pack backend for the main repository *but* both of them will be checked
before any loose backends.

We moved the "main" parsing to use 64 bits for the timestamp, but the
quick parsing for the revwalk did not. This means that for large
timestamps we fail to parse the time and thus the walk.

Move this parser to use 64 bits as well.

xdiff craps the bed on large files.  Treat very large files as binary,
so that it doesn't even have to try.

Refactor our merge binary handling to better match git.git, which
looks for a NUL in the first 8000 bytes.

As refdb and odb backends can be allocated by client code, libgit2
can’t know whether an alternative memory allocator was used, and thus
should not try to call `git__free` on those objects.

Instead, odb and refdb backend implementations must always provide
their own `free` functions to ensure memory gets freed correctly.

When we do not trust the on-disk mode, we use the mode of an existing
index entry.  This allows us to preserve executable bits on platforms
that do not honor them on the filesystem.

If there is no stage 0 index entry, also look at conflicts to attempt
to answer this question:  prefer the data from the 'ours' side, then
the 'theirs' side before falling back to the common ancestor.

Include custom HTTP headers