Converting Apple Lossless to FLAC?

Hello. I was looking around here and the internet for some info about converting Apple Lossless files over to FLAC, now that Windows Media Player directly supports FLAC in Windows 10. I see a lot of talk about converting *to* Apple Lossless from FLAC, but I want to go the other direction ... take a bunch of .m4a and get them into FLAC/WMP. The plan going forward now is to rip everything into FLAC since I've heard that's the cleanest file as far as lossless codecs go.

FWIW, I'm using Sonos for playback from network storage. I don't really play back from WMP or iTunes much, so it's not really a matter of which program plays things back better or not. It's all about media management, and I've just about reached my limit with iTunes's idiosyncrasies. My tech is entirely a Windows ecosystem as it is; only used iTunes because it was the given standard for lossless, and I had an iPod that I was using only because I was compelled into iTunes for the lossless.

Any advice or pointers on converting from .m4a to .flac would be greatly appreciated.