gcc ignores locale (no UTF-8 source code supported)

[Joern Rennecke]

> For gcc, the issue is both one of portability and performance: the
> wide character routines are not available on supported hosts, and the
> performance hit of calling mb* routines would be unacceptable. Only

You could autoconf for the existence of the wide character routines.
And when starting the preprocessor, you can check which 8-bit raw
characters map to a full wide character, and build a lookup table;
when doing lexical scanning, you can then fast-track the 8 bit characters.