Merge branch 'master' into python3-ci

* master: (28 commits)
  Update README to combine environment sections
  Update README
  os.path.samefile is not available on windows.
  Add shell-style execution on the Mac
  Use os.path.samefile to get around filename case insensitivity
  Add test for before_build executing in a shell
  Fix some linter warnings
  Add CIBW_ENVIRONMENT to README and reorder options
  Fix empty env string case
  Fix string splitting for the env string
  Making call from run_tests to run_test subprocess.check_call
  Fixing 'ValueError: Attempted relative import in non-package'
  Update README.md
  Reducing code duplication in bin/run_test.py and bin/run_tests.py
  Semicolons need quoting
  Ignore vscode project settings
  Windows uses a different pathsep so have to use that in the test
  Make shell evals work and add tests for that
  Use parse_environment in the main code
  Run the unit tests in CI
  ...

# Conflicts:
#	.travis.yml
#	appveyor.yml
#	run_tests.py

cibuildwheel/windows.py

@@ -10,7 +10,7 @@ from glob import glob
 from .util import prepare_command, Unbuffered
 
 
-def build(project_dir, package_name, output_dir, test_command, test_requires, before_build, skip):
+def build(project_dir, package_name, output_dir, test_command, test_requires, before_build, skip, environment):
     # Python under AppVeyor/Windows seems to be buffering by default, giving problems interleaving subprocess call output with unflushed calls to 'print'
     sys.stdout.flush()
     sys.stdout = Unbuffered(sys.stdout)
@@ -64,6 +64,7 @@ def build(project_dir, package_name, output_dir, test_command, test_requires, be
             os.path.join(config.path, 'Scripts'),
             env['PATH']
         ])
+        env = environment.as_dictionary(prev_environment=env)
 
         # for the logs - check we're running the right version of python
         shell(['python', '--version'], env=env)