[libcpp] Disable cb.line_change callbacks from within cpp_peek_token (PR preprocessor/61977)

[Jakub Jelinek]

On Wed, Apr 01, 2015 at 04:23:12PM -0400, Jason Merrill wrote:
> On 04/01/2015 07:24 AM, Jakub Jelinek wrote:
> >Below is one possible fix for that, another option is introduce another
> >pfile->state or pfile field for that,
> 
> I notice that pfile->state.skipping suppresses the line change as well as
> various diagnostics that also seem inappropriate for peeking. Perhaps we
> could use a new state field instead in those places, and only check
> state.skipping for the actual skipping behavior.

I was thinking about that, but e.g. warnings like warn_about_normalization
only happen during _cpp_lex_direct and thus would not be reported at all
if they were skipped during cpp_peek_token.

	Jakub