rust frontend and UTF-8/unicode processing/properties

[Manuel López-Ibáñez]

> For the gcc rust frontend I was thinking of importing a couple of
> gnulib modules to help with UTF-8 processing, conversion to/from
> unicode codepoints and determining various properties of those
> codepoints. But it seems gcc doesn't yet have any gnulib modules
> imported, and maybe other frontends already have helpers to this that
> the gcc rust frontend could reuse.

Although I agree that factoring out the code in libcpp so that it can be used 
by other FEs would be great and in line with the goals of 
https://gcc.gnu.org/wiki/ModularGCC that is a significant amount of work. 
Importing gnulib has its own advantages and it would allow GCC to finally 
deprecate libiberty:

https://gcc.gnu.org/wiki/replacelibibertywithgnulib

There is a preliminary patch here: 
https://gcc.gnu.org/legacy-ml/gcc-patches/2016-08/msg01554.html

Cheers,

Manuel.