This adds git_path_icmp to complement git_path_cmp.

The usage of the Android derrived code contains a full notice
which must be provided with the source code as per the terms
given at:
https://android.googlesource.com/platform/bionic/+/android-4.0.3_r1.1/libc/bionic/dirname_r.c

The usage of the Android derrived code contains a full notice
which must be provided with the source code as per the terms
given at:
https://android.googlesource.com/platform/bionic/+/android-4.0.3_r1.1/libc/bionic/dirname_r.c

Fix libgit2/libgit2sharp#256

The `git_iterator_reset` command has not been working in all cases
particularly when there is a start and end range.  This fixes it
and adds tests for it, and also extends it with the ability to
update the start/end range strings when an iterator is reset.

There are many scattered functions that look into the contents of
buffers to do various text manipulations (such as escaping or
unescaping data, calculating text stats, guessing if content is
binary, etc).  This groups all those functions together into a
new file and converts the code to use that.

This has two enhancements to existing functionality.  The old
text stats function is significantly rewritten and the BOM
detection code was extended (although largely we can't deal with
anything other than a UTF8 BOM).

This is a major reworking of checkout strategy options.  The
checkout code is now sensitive to the contents of the HEAD tree
and the new options allow you to update the working tree so that
it will match the index content only when it previously matched
the contents of the HEAD.  This allows you to, for example, to
distinguish between removing files that are in the HEAD but not
in the index, vs just removing all untracked files.

Because of various corner cases that arise, etc., this required
some additional capabilities in rmdir and other utility functions.

This includes the beginnings of an implementation of code to read
a partial tree into the index based on a pathspec, but that is
not enabled because of the possibility of creating conflicting
index entries.

This extends git_repository_init_ext further with support for
initializing the repository from an external template directory
and with support for the "create shared" type flags that make a
set GID repository directory.

This also adds tests for much of the new functionality to the
existing `repo/init.c` test suite.

Also, this adds a bunch of new utility functions including a
very general purpose `git_futils_mkdir` (with the ability to
make paths and to chmod the paths post-creation) and a file
tree copying function `git_futils_cp_r`.  Also, this includes
some new path functions that were useful to keep the code
simple.

Signed-off-by: Ben Straub <bstraub@github.com>

Also, remove some duplication in the clone test
suite.

This makes it easy to take a buffer containing a path with relative
references (i.e. .. or . path segments) and resolve all of those
into a clean path.  This can be applied to URLs as well as file
paths which can be useful.

As part of this, I made the drive-letter detection apply on all
platforms, not just windows.  If you give a path that looks like
"c:/..." on any platform, it seems like we might as well detect
that as a rooted path.  I suppose if you create a directory named
"x:" on another platform and want to use that as the beginning
of a relative path under the root directory of your repo, this
could cause a problem, but then it seems like you're asking for
trouble.

On GNU, the d_name field of the dirent structure is defined as "char d_name[1]",
so we must allocate more than sizeof(struct dirent) bytes, just like on Sun.

Needs AmigaOS.cmake now from CMake package at OS4Depot, or contents below:
--8<--
SET(AMIGA 1)
SET(CMAKE_SHARED_LIBRARY_C_FLAGS "-fPIC")
SET(CMAKE_SHARED_LIBRARY_CREATE_C_FLAGS "-shared")
--8<--

Missed a place that used this and missed git__isalpha

When checking for a drive letter on windows, instead of using
isalpha(), it is better to just check for a..z and A..Z, I think,
particularly because the MS isalpha implementation appears to
assert when given an 0xFF byte.

On Solaris, struct dirent is defined differently than Linux. The field
containing the path name is of size 0, rather than NAME_MAX. So, we need to
use a properly sized buffer on Solaris to avoid a stack overflow.

Also fix some DIR* leaks on cleanup.

compat: make p_realpath Windows implementation be a bit more POSIX compliant and fail if the provided path does not lead to an existing entry

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

This fixes all the warnings on win64 except those in deps, which
come from the regex code.

Add a new command `git_repository_open_ext` with extended options
that control how searching for a repository will be done.  The
existing `git_repository_open` and `git_repository_discover` are
reimplemented on top of it.  We may want to change the default
behavior of `git_repository_open` but this commit does not do that.

Improve support for "gitdir" files where the work dir is separate
from the repo and support for the "separate-git-dir" config.  Also,
add support for opening repos created with `git-new-workdir` script
(although I have only confirmed that they can be opened, not that
all functions work correctly).

There are also a few minor changes that came up:

- Fix `git_path_prettify` to allow in-place prettifying.

- Fix `git_path_root` to support backslashes on Win32.  This fix
  should help many repo open/discover scenarios - it is the one
  function called when opening before prettifying the path.

- Tweak `git_config_get_string` to set the "out" pointer to NULL
  if the config value is not found.  Allows some other cleanup.

- Fix a couple places that should have been calling
  `git_repository_config__weakptr` and were not.

- Fix `cl_git_sandbox_init` clar helper to support bare repos.

Also cleaned up some previously converted code that still had
little things to polish.

Fix libgit2/libgit2sharp#125

This converts blob.c, fileops.c, and all of the win32 files.
Also, various minor cleanups throughout the code.  Plus, in
testing the win32 build, I cleaned up a bunch (although not
all) of the warnings with the 64-bit build.

This continues to add other files to the new error handling
style.  I think the only real concerns here are that there are
a couple of error return cases that I have converted to asserts,
but I think that it was the correct thing to do given the new
error style.

Ended up migrating a bunch of upstream functions as well
including vector, attr_file, and odb in order to get this
to work right.

This also includes droping `git_buf_lasterror` because it makes no sense
in the new system. Note that in most of the places were it has been
dropped, the code needs cleanup. I.e. GIT_ENOMEM is going away, so
instead it should return a generic `-1` and obviously not throw
anything.