[Picolibc] Integrating Picolibc into a GCC toolchain

[R. Diez]

>> https://github.com/rdiez/JtagDue/blob/master/Toolchain/Tools/GeneratePicolibcCrossFile.sh
> 
> [...]
> This uses the first element of the target architecture for the cpu
> family name by default, 

I'll try to implement that in the next days without using the external tool 'expr'.


> then can use the cpu family name for the cpu name.

I have added that default to the script.


> I also stuck in a few common cpu families to set the endianness value,
> but that probably should just be required to be more consistent.

I think providing a default is reasonable, so I added it to the script.

We can disable it later if you think that a default is causing too much trouble.

We could also introduce a new value: --endianness=default or --endianness=family-default

But I wonder how many architectures would actually be affected by a bad default.


> I'll see if I can't install it somewhere that a user could find it without
> sticking it in /bin, although /bin may be the best we can manage :-)

Subdirectory "/bin" seems reasonable, but I am not familiar enough with the Unix directory name conventions.


Best regards,
   rdiez