There are several places where users may want to specify the type of
object IDs (sha1 or sha256) that should be used, for example, when
dealing with repositories, indexes, etc.
However, given that sha256 support remains disappointingly uncommon in
the wild, we should avoid hard API breaks when possible. Instead, update
these APIs to have an "extended" format (eg, `git_odb_open_ext`) that
provides an options structure with oid type information.
This allows callers who do care about sha256 to use it, and callers who
do not to avoid gratuitous API breakage.
When iterating over index entries, we store the indices in an unsigned
int. As the index entrycount is a `size_t` though, this may be a loss of
precision which a compiler might rightfully complain about.
Use `size_t` instead to fix any warnings.
Inside of our networking example code, we have a git2 executable
that acts as an entry point to all the different network
examples. As such, it is kind of the same like the normal git(1)
executable in that it simply arbitrates to the respective
subcommands.
Let's extend this approach and merge all examples into a single
standalone lg2 executable. Instead of building an executable
for all the existing examples we have, we now bundle them all
inside of the lg2 one and let them be callable via subcommands.
In the process, we can get rid of duplicated library
initialization, deinitialization and repository discovery code.
Instead of having each subcommand handle these on its own, we
simply do it inside of the single main function now.
