tzcode: Update to 2021c
tzcode: Update to 2021c

Some cleanup also
JPeterMugaas/MSYS2-packages,JPeterMugaas/MSYS2-packages,waterlan/MSYS2-packages,waterlan/MSYS2-packages,mati865/MSYS2-packages,mati865/MSYS2-packages,mati865/MSYS2-packages,JPeterMugaas/MSYS2-packages,waterlan/MSYS2-packages,waterlan/MSYS2-packages,JPeterMugaas/MSYS2-packages,mati865/MSYS2-packages