Add hghave utility and run-tests.py support.
hghave detects system features like symlinks availability at run-time. Tests can be skipped by starting them with:
"$TESTDIR/hghave" symlink || exit 80
The 80 exit status triggers hghave output handling by run-tests.py. Also, tests output can be locally patched on the fly to match reference output.
% pattern error
grep: invalid match pattern: nothing to repeat!
% simple
port:4:export
port:4:vaportight
port:4:import/export
% all
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import
% other
port:4:import/export
% follow
port:0:import
port2:6:4:+:eggs:deport
port:4:4:-:spam:import/export
port:3:4:+:eggs:import/export
port:2:1:-:spam:import
port:2:2:-:spam:export
port:2:1:+:spam:export
port:2:2:+:spam:vaportight
port:2:3:+:spam:import/export
port:1:2:+:eggs:export
port:0:1:+:spam:import
color:3:orange
color:3:+:orange
color:2:-:orange
color:1:+:orange