* Introduce a python script to generate the USB descriptor instead of
a bunch of C macros. In the future, we can use this dynamically in
CircuitPython.
* Add support for detecting read-only mass storage mounts.
Fixes#377
* Revert "Read serial input as a background task so we can check for the interrupt character."
This reverts commit 046092e8a2.
* Revert "Check INTERNAL_LIBM make flag in a safer way."
This reverts commit 2b80add22f.