lang/micropython: Update to 1.17

• Switch to GCC because building with Clang leads to a broken "mpy-cross" binary, which segfaults if issued with several parameters during build.

• REINPLACE_CMD should not be used to replace static content, hence convert those occurrences into patches.

• Also update pkg-descr and sort variables a bit according to the PHB.

Reviewed by: decke (earlier revision)
Approved by: kai (python, maintainer)
Differential Revision: https://reviews.freebsd.org/D31855