* Added `std.c.unlinkat` and `std.os.unlinkat`.
* Removed `std.fs.MAX_BUF_BYTES` (this declaration never made it to
master branch)
* Added `std.fs.Dir.deleteTree` to be used on an open directory handle.
* `std.fs.deleteTree` has better behavior for both relative and
absolute paths. For absolute paths, it opens the base directory
and uses that handle for subsequent operations. For relative paths,
it does a similar strategy, using the cwd handle.
* The error set of `std.fs.deleteTree` is improved to no longer have
these possible errors:
- OutOfMemory
- FileTooBig
- IsDir
- DirNotEmpty
- PathAlreadyExists
- NoSpaceLeft
* Added `std.fs.Dir.posix_cwd` which is a statically initialized
directory representing the current working directory.
* The error set of `std.Dir.open` is improved to no longer have these
possible errors:
- FileTooBig
- IsDir
- NoSpaceLeft
- PathAlreadyExists
- OutOfMemory
* Added more alternative functions to `std.fs` for when the path
parameter is a null terminated string. This can sometimes be more
effecient on systems which have an ABI based on null terminated
strings.
* Added `std.fs.Dir.openDir`, `std.fs.Dir.deleteFile`, and
`std.fs.Dir.deleteDir` which all operate on an open directory handle.
* `std.fs.Walker.Entry` now has a `dir` field, which can be used to do
operations directly on `std.fs.Walker.Entry.basename`, avoiding
`error.NameTooLong` for deeply nested paths.
* Added more docs to `std.os.OpenError`
This commit does the POSIX components for these changes. I plan to
follow up shortly with a commit for Windows.
* `std.os.execve` had the wrong name; it should have been
`std.os.execvpe`. This is now corrected.
* introduce `std.os.execveC` which does not look at PATH, and uses
null terminated parameters, matching POSIX ABIs. It does not
require an allocator.
* fix typo nonsense doc comment in `std.fs.MAX_PATH_BYTES`.
* introduce `std.os.execvpeC`, which is like `execvpe` except it
uses null terminated parameters, matching POSIX ABIs, and thus
does not require an allocator.
* `std.os.execvpe` implementation is reworked to only convert
parameters and then delegate to `std.os.execvpeC`.
* `std.os.execvpeC` improved to handle `ENOTDIR`. See #3415
