preprocessor/9449: UCNs recognized in identifiers (c++/c99)

[rearnsha@arm.com]

>Number:         9449
>Category:       preprocessor
>Synopsis:       UCNs recognized in identifiers (c++/c99)
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          rejects-legal
>Submitter-Id:   net
>Arrival-Date:   Mon Jan 27 14:56:00 UTC 2003
>Closed-Date:
>Last-Modified:
>Originator:     Richard Earnshaw
>Release:        unknown-1.0
>Organization:
>Environment:
Any
>Description:
(I've marked this as "preprocessor" since that's used for lexing both C99 and C++, but this is probably more complicated that that...)

The following is legal in both c99 and C++, but is rejected by both:

int x\u0394;

Note that this isn't just an issue of parsing the input.  The correct translation to the target symbol is also required (this my be governed by machine conventions and/or object file  or linker restrictions).
>How-To-Repeat:
compile the example above with -std=c99 (for C) or the C++ compiler.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: