Update binutils + LLVM

[lenary]

We should start planning an update to the toolchain to bring in more up to date LLVM features and a more recent binutils/gcc version.

There's no specific urgency here, but it would be good to try to stay ahead of the curve.

Software	Current Version (20200626-1)	Current Released Version (2020-09-22)
binutils	2.32	2.35.1
gcc	9.2.0	10.2.0
newlib	3.1.0-20181231	3.2.0 (snapshotted two days later, but there are fixes in HEAD for risc-v).
gdb	8.2.1	9.2
llvm	fa038e03504c7d0dfd438b1dfdd6da7081e75617 (2020-05-25)	11 is coming soon.

I'm not sure how up-to-date crosstool-ng's sources are, which may give some problems here, but we have our own fork with our own patches anyway.

[lenary]

#37 Is the main thrust of this update.