feat: creating and removing empty directories

[wassup05]

User facing functions added are

• make_directory (path, mode, err) (mode argument only for Unix systems)
• remove_directory (path, err)

1. Both of them support relative paths and on Windows, paths involving either / or \.
2. They bind to the CRT functions mkdir, rmdir, _mkdir, _rmdir on Unix and Windows respectively.
3. A binding to strerror has been included as a private helper to provide helpful error messages.
4. state_type is used for error handling.

Side note:
make_directory could have a logical argument recursive which would work like mkdir -p but that would require path manipulation especially dir_name from #999

Do let me know your thoughts.

[sebastian-mutz]

Hey @wassup05. Thanks for the PR. Great work!

1. I added minor suggestions to the comments (just grammar).
2. For example_remove_directory, I wonder if it makes sense to first create the directory. Ideally an example only demonstrates the use of one procedure, but without the existing directory, it can't. Just a thought and nothing major.

[sebastian-mutz]

Add period to end of sentence.

[sebastian-mutz]

Capitalise "appropriate" to be consistent. (Same down below).

[wassup05]

For example_remove_directory, I wonder if it makes sense to first create the directory. Ideally an example only demonstrates the use of one procedure, but without the existing directory, it can't. Just a thought and nothing major.

I think it's fine @sebastian-mutz, doing that would kind of clutter the example I feel, and this is how it's been handled in some other examples as well like here and here

[sebastian-mutz]

For example_remove_directory, I wonder if it makes sense to first create the directory. Ideally an example only demonstrates the use of one procedure, but without the existing directory, it can't. Just a thought and nothing major.

I think it's fine @sebastian-mutz, doing that would kind of clutter the example I feel, and this is how it's been handled in some other examples as well like here and here

Makes sense. Then it's best to keep it consistent.