mpy-cross fails to compile in mingw32
When I first started working with the esp32 I found that using the Windows toolchain/mingw32 environment from Espressif was extremely slow. As I generally prefer using Windows as my Desktop OS I had setup a remote CDT environment using my Linux server to compile & debug the firmware while using Eclipse on Windows. Unfortunately my PC died a few weeks ago and when I finally got a new one last week I tought I'd try the latest Espressif mingw32 environment again and it now seems to work just as good as the Linux one.
However I did run into a small issue when trying to build mpy-cross in the environment. Thankfully I found that this is a known issue: https://github.com/micropython/micropython/issues/2298
This pull request fixes the issue for me. I tested it on both Windows 10 x64 with the latest mingw32 environment published by Espressif linked above and on Ubuntu 17.04 to make sure it does not break my Linux server environment.
I'd be happy to create a pull request for the current pycom-micropython-sigfox firmware.