PiBox

Added -predownload target but this isn't actually necessary. Crosstool-NG 1.24 has experimental features that allow using git archives, which is how the current builds work. I just need to add this feature to the new pre-RPi HW type/bit config files.

This is testing now for rpi3 @ 64bit.

Okay, isl can use the experimental feature but expat can't (master doesn't build). So using the predownload feature is needed for expat.

This is mostly done but there are problems. The 64bit toolchains don't build the 5.10.y kernel. But 5.10.y isn't even an active tag on the RPi github repo anymore. So I need to bump to the latest active, which is 5.15.y.

This is more complex than I expected so this will go into a branch - RM838. I'll return to it after I finish the 2.0 release (which I may not be able to do until I bump the kernel anyway).

This no longer seems to be an issue with the latest Crosstool-NG after bumping to 1.25 for PiBox v3.0.

Closing issue.