Merge remote-tracking branch 'origin/master' into azure-windows

README.md

@@ -240,9 +240,8 @@ Options
 -------
 
 ```
-usage: cibuildwheel [-h]
-                    [--output-dir OUTPUT_DIR]
-                    [--platform PLATFORM]
+usage: cibuildwheel [-h] [--platform {auto,linux,macos,windows}]
+                    [--output-dir OUTPUT_DIR] [--print-build-identifiers]
                     [project_dir]
     
 Build wheels for all the platforms.
@@ -262,7 +261,10 @@ optional arguments:
                         you need to run in Windows, and it will build and test
                         for all versions of Python at C:\PythonXX[-x64].
   --output-dir OUTPUT_DIR
-                        Destination folder for the wheels. 
+                        Destination folder for the wheels.
+  --print-build-identifiers
+                        Print the build identifiers matched by the current
+                        invocation and exit.
 
 ```
 
@@ -469,6 +471,7 @@ If your wheel didn't compile, check the list below for some debugging tips.
 - A mistake in your config. To quickly test your config without doing a git push and waiting for your code to build on CI, you can run the Linux build in a Docker container. On Mac or Linux, with Docker running, try `cibuildwheel --platform linux`. You'll have to bring your config into the current environment first.
 - Missing dependency. You might need to install something on the build machine. You can do this in `.travis.yml`, `appveyor.yml`, or `.circleci/config.yml`, with apt-get, brew or whatever Windows uses :P . Given how the Linux build works, we'll probably have to build something into `cibuildwheel`. Let's chat about that over in the issues!
 - Windows: missing C feature. The Windows C compiler doesn't support C language features invented after 1990, so you'll have to backport your C code to C90. For me, this mostly involved putting my variable declarations at the top of the function like an animal.
+- MacOS: calling cibuildwheel from a python3 script and getting a `ModuleNotFoundError`? Due to a [bug](https://bugs.python.org/issue22490) in CPython, you'll need to [unset the `__PYVENV_LAUNCHER__` variable](https://github.com/joerick/cibuildwheel/issues/133#issuecomment-478288597) before activating a venv.
 
 Working examples
 ----------------