When enabled, man pages are generated and installed, along with
README.md, CHANGELOG.md and LICENSE. This requires ‘scdoc’ as a make
dependency.
When disabled, ‘scdoc’ is no longer required, no man pages will be
built, and no documentation at all is installed.
Defaults to ‘enabled’.
run_command() was only run at configure time, meaning the generated
version (that was passed on to the sources via -DFUZZEL_VERSION)
became stale.
Fix by implementing a shell script that generates a header file, and
wrap this in a custom target that is run every time (but the generated
file is only updated when the version changes)
