Newer less versions appear to have changed how stderr
and stdout are showing error messages. hardcode the
expected behavior to make the tests pass with any less version.
Also set locale to C so that the strings are matching.
The zstd symlinks, notably `zstdcat`, weren't working as expected
because only the `tests/cli-tests/bin/zstd` wrapper was symlinked. We
still invoked `zstd` with the name `zstd`. The fix is to create a
directory of zstd symlinks in `tests/cli-tests/bin/symlinks` for each
name that zstd recognizes. And when `tets/cli-tests/bin/zstd` is
invoked, it selects the correct symlink to call.
See the test `zstd-cli/zstdcat.sh` for an example of how it would work.
* playtests.sh: fix for a bug in macos' /bin/sh that persists temporary env vars when introduced before function calls
* cli-tests/run.py: Do not use existing ZSTD* envvars
Dirk Müller