Fix yamllint error
Build with ANSI C (c89) without errors

Issue: https://todo.sr.ht/~ancarda/picotest/2
Drop unnecessary semicolon

I thought this was required by `IT_SHOULD', but it's actually just the
internal tests being a bit odd.

This now runs cleanly with `-Wpedantic'.

Issue: https://todo.sr.ht/~ancarda/picotest/1
Build on Clang as well as GCC
Add CONTRIBUTING file and links in README
Show project name rather than GitHub ID
SPDX Identifiers for current license
Add builds.sr.ht shield
Migrate to builds.sr.ht

This commit completes the move away from GitHub and other proprietary software!
Fix `make format'
Don't set CC in Makefile
Re-license as AGPLv3
Remove GitHub Actions hook

This commit removes everything in the `.github' directory as this repo is
moving to SourceHut
Improve documentation
Format code with clang, run tests with Makefile
Nicer include guards
Remove cast to void

This was put in place for static analysis (splint) which is no longer
needed given compilers are getting better at that job
Use include guards over pragma once

This reduces warnings when using compilers that do not support
`#pragma once`.
Framework consistency
Wrap strings for easier comparison