Add licensing and copyright information for all files in this repository. This
either happens in the file itself as a comment header or in the file
`.reuse/dep5`.
This commit also adds a Github workflow to check pull requests and adapts
copyright.pl to the changes.
Closes#8869
This warning used to be enabled only for clang as it's a bit stricter
on GCC. Silence the remaining occurrences and enable it on GCC too.
Closes https://github.com/curl/curl/pull/2747
Now that the form API is deprecated and not used anymore in curl tool,
a lot of its features left untested. Test 650 attempts to check all these
features not tested elsewhere.