Meson already works like that, except in do_copydir() that requires
absolute destdir. Better explicitly support that instead of leaving it
undefined and unconsistent.
This moves all the code into a class and call its run() method in a
thread. The class queues all logs to print them at the end to avoid
mixing output of multiple actions.
It requires at least one option argument, and the one that provides
"basic information" about the project is --projectinfo, so let's use
that to demo the command.
Fixes#8182
* doc: fix hotdoc misuse for dynamically generated content
hotdoc has a native include feature for including files inline. Use this
to generate one file for each dynamically generated code block, and
include that file in Commands.md; see:
https://hotdoc.github.io/syntax-extensions.html#smart-file-inclusion-syntax
This permits us to move back to using the in-tree version of the hotdoc
*.md sources, thus fixing the incorrect inclusion of "builddir/" in the
"Edit on github" links which resulted from using copies as the source.
Fixes#8061
* doc: call the dummy file a "stamp" as it is a better known term