wc: Clean up and modernize.

[des]

Summary

• Drop <err.h>, which is unnecessary since we use libxo.

• As per POSIX, report an error if output fails.

• Fix some type mismatches.

• Use bool instead of int where appropriate.

• Avoid repeatedly checking for a null filename.

• Miscellaneous other tidying.

• Add tests (partly derived from work performed by SHENG-YI HONG <[e-mail]>).

Sponsored by: Klara, Inc.

[des]

Avoid repeatedly checking for a null filename.

[des]

Switch mbrtowc() cases around to avoid awkward line wrapping.

[des]

Avoid needless repetitions of a hardcoded buffer size.

[des]

Add tests.

[des]

Remove unintended test file.

[des]

Fix multiline_repeated test.

[des]

Fix exit codes.

[des]

*sigh* I keep finding more stuff to fix

[lwhsu]

I also have some WIP tests for wc(1) to be added in D35877

[des]

Use printf(1) instead of echo.
Add a test case with only blank lines.
Add a test case with only whitespace.

[des]

In D38496#876169, @lwhsu wrote:

I also have some WIP tests for wc(1) to be added in D35877

It's unfortunate that this wasn't approved back in the day. Does it cover anything that my tests don't?

[lwhsu]

In D38496#877177, @des wrote:

In D38496#876169, @lwhsu wrote:

I also have some WIP tests for wc(1) to be added in D35877

It's unfortunate that this wasn't approved back in the day. Does it cover anything that my tests don't?

It's my fault that haven't completed it yet but I do plan to work on it with the submitter this week. Do you mind if I go ahead to remove the duplicated ones in D35877 and merge it first? Or you want to get this differential in first? I proposed to add tests first because it would be a good practice for code refactoring, but I can wait if you want.

[des]

Add descriptions to test cases.

[des]

In D38496#877219, @lwhsu wrote:

In D38496#877177, @des wrote:

In D38496#876169, @lwhsu wrote:

I also have some WIP tests for wc(1) to be added in D35877

It's unfortunate that this wasn't approved back in the day. Does it cover anything that my tests don't?

It's my fault that haven't completed it yet but I do plan to work on it with the submitter this week. Do you mind if I go ahead to remove the duplicated ones in D35877 and merge it first? Or you want to get this differential in first? I proposed to add tests first because it would be a good practice for code refactoring, but I can wait if you want.

How about we add a comment to wc_test.sh crediting the student?

[des]

Add a few more test and fix the whitespace test.

[des]

Nit: alphabetize envars.