tests/test-hghave.t

setup: drop the hack to disable linker warning 4197 on Windows

I don't see this when building on Windows with py3.8 or py3.12, so either the
code was fixed, or (more likely) the compiler stopped warning about it some time
after VS 2008.  If we do have to put this back, it would probably be better to
put a `#pragma` in a header file somewhere, and avoid `setuptools` technical
debt.

  $ . "$TESTDIR/helpers-testrepo.sh"

Testing that hghave does not crash when checking features

  $ hghave --test-features 2>/dev/null

Testing hghave extensibility for third party tools

  $ cat > hghaveaddon.py <<EOF
  > import hghave
  > @hghave.check("custom", "custom hghave feature")
  > def has_custom():
  >     return True
  > EOF

(invocation via run-tests.py)

  $ cat > test-hghaveaddon.t <<EOF
  > #require custom
  >   $ echo foo
  >   foo
  > EOF
  $ ( \
  > testrepohgenv; \
  > "$PYTHON" $TESTDIR/run-tests.py --with-hg=$HGTEST_REAL_HG -j 1 \
  >    $HGTEST_RUN_TESTS_PURE test-hghaveaddon.t \
  > )
  installed Mercurial in * seconds  (glob) (?)
  running 1 tests using 1 parallel processes 
  .
  # Ran 1 tests, 0 skipped, 0 failed.

(invocation via command line)

  $ unset TESTDIR
  $ hghave custom

(terminate with exit code 2 at failure of importing hghaveaddon.py)

  $ rm hghaveaddon.*
  $ cat > hghaveaddon.py <<NO_CHECK_EOF
  > importing this file should cause syntax error
  > NO_CHECK_EOF

  $ hghave custom
  failed to import hghaveaddon.py from '.': invalid syntax (hghaveaddon.py, line 1)
  [2]