Before this patch, test-check-config.t fails on Solaris, because
"xargs" doesn't invoke check-config.py with all filenames at once.
"xargs" may invoke specified command multiple times with part of
arguments given from stdin: according to "xargs(1)" man page, this
dividing arguments is system-dependent.
For portability of test-check-config.t, this patch adds "xargs" like
mode to check-config.py and executes it in test-check-config.t without
"xargs".
This script scans files for lines that look like either ui.config
usage or config variable documentation. It then ensures:
- ui.config calls for each option agree on types and defaults
- every option appears to be mentioned in documentation
It doesn't complain about devel/experimental options and allows
marking options that are not intended to be public.
Since we haven't been able to come up with a good scheme for
documenting config options at point of use, this will help close the
loop of making sure all options that should be documented are.
