Apply recent LLVM-ET changes to ATfE
After the import of the LLVM-ET build scripts, additional changes were made to that repo that are also required here:
- Changes to AArch64 nofp variant (#589)
- Remaster picolibc patches against commit e3a4f137d85c5e9 (#590)
- Fix build failures in aarch64a_[be_]soft_nofp variants. (#591)
- Do not build AArch64a soft no_fp variants using llvm-libc (#592)
- Fix delimiter so CMake reads string as a list (#593)
These applied without confict, but with the paths prefixed with arm-software/embedded to account for the new location.
Edited by David Candler