walk: we always have a badfn

walk: simplify check for missing file

run-tests: redefine --with-hg so it takes the 'hg' script to run. - in parseargs(), check that --with-hg value is valid - add handy --local option for "--with-hg=../hg" - ensure that we always set PATH and PYTHONPATH (not just when doing a temporary install) - override any existing PYTHONPATH, so test success does not depend on whatever happens to be in the caller's environment - give tests a little more control by exporting $PYTHON to the environment; needed by test-convert and test-mergetool when they run hg with a stripped-down $PATH Also, add a big comment explaining all the corner cases to test for the next person who tries to modify this script.

run-tests: fix _checkhglib() so it's correct when using --with-hg. Since this makes the warning less likely, upgrade it to a "real" warning to stderr.

run-tests: factor out _checkhglib() to check import path of 'mercurial'. - rename _hgpath() to _gethgpath() and move it down next to _checkhglib() - change _gethgpath() so it caches its result: replaces global 'hgpkg' that anyone can use with global '_hgpath' that is only for _gethgpath() - no need to pass 'expecthg' to runchildren() or runtests() anymore Also: do not change global PYTHON when doing coverage; this seems to be unnecessary, since we create a dummy 'hg' script that handles coverage for us, and it made things brittle. (E.g. the rest of this patch makes the call to _hgpath() come later, and it was broken by enabling coverage.)

run-tests: show PID if running in parallel mode with -v. (Extremely handy when you break parallel operation and need to figure out what's going on. The assumption is that if you run with -v, you want more details.)

i18n-da: synchronized and updated slightly