[RFA] nuke CONST_PTR

[Andrew Cagney]

> In gdb 4.18 and gdb 5.0, CONST_PTR was conditionally defined as nothing
>> if MSC_VER was defined, and "const" otherwise.  In gdb 5.1 and gdb 5.1.1,
>> CONST_PTR is always defined to "const".  So CONST_PTR has been
>> unconditionally defined for only a few months.
>> 
>> However, in gdb 4.18, gdb 5.0, gdb 5.1, and gdb 5.1, c-lang.c has also
>> contained this line:
>> 
>> struct type **const (cplus_builtin_types[]) =
>> 
>> So this form has been in gdb source code for four releases already
>> without drawing complaint.
>> 
>> Testing: I built this on native i686-pc-linux-gnu and ran the test suite.
>> 
>> Okay to apply?
> 
> 
> Your reasoning seems good, but your testing doesn't.
> Seems to me you need to test this when building with Microsoft C.
> 
> OTOH, do we ever build with Microsoft C any more?
> Is there any reason to support it?  Cygwin and Djgcc
> are both self-hosting, aren't they?

Not since '98!  The line:

 >> struct type **const (cplus_builtin_types[]) =

was added in '98 so ever since then GDB hasn't been able to build with 
the MSC compiler CONST_PTR was working around.  As Michael pointed out, 
we've had 4 releases since then.

enjoy,
Andrew