[Picolibc] Integrating Picolibc into a GCC toolchain

[R. Diez]

> I think using command line parameters would probably be cleaner;
> [...]

OK, take a look at the first version of the script:

https://github.com/rdiez/JtagDue/blob/master/Toolchain/Tools/GeneratePicolibcCrossFile.sh

Setting c_ld is still missing, and maybe others. But I wonder whether we need those in this script. After all, such settings are for testing Picolibc, and the user will always have his/her own project that specifies how to link the embedded application.

Regards,
  rdiez