[Predef-contribute] __STDC_ISO_10646__

[Martin M. <mar...@up...>]

Hi.

I think __STDC_ISO_10646__ should be added.

In short if this macro is defined, and sizeof(wchar_t) =3D=3D4,
then wide strings on the platform are guaranteed to use
UCS-4 encoding.

If the macro is defined and sizeof(wchar_t) =3D=3D 2, the wide=20
strings on the platform are guaranteed to use UCS-2.

Value of the macro (if defined)  specifies year and month=20
of the unicode standard version it's used.

E.g.=20
#define __STDC_ISO_10646__   200009L
means that the corresponding Unicode standard was=20
released in September 2000, i.e. it's Unicode 3.0.

Not sure however whether it's job of libc or compiler=20
to define this macro.

Mity

P.S. Thanks for your work on http://predef.sourceforge.net.=20
It's _VERY_ useful for me.