PATCH: --with-build-sysroot, et. al.

[Mark Mitchell]

Geoff Keating wrote:

>> @item -isysroot @var{dir}
>> @opindex isysroot
>> This option is like the @option{--sysroot} option, but applies only to
>> header files.  See the @option{--sysroot} option for more information.
> 
> On Darwin, -isysroot applies to both header files and libraries.

OK, I agree that's inaccurate -- though it's rather extreme to call that 
a regression, since before the option was totally undocumented.

Please file a PR, and assign it to me.

Thanks,

-- 
Mark Mitchell
CodeSourcery, LLC
mark@codesourcery.com
(916) 791-8304