preprocessor/10613: Please make -Wtrigraphs the default

[Neil Booth]

Hallvard B Furuseth wrote:-

> No.  -Wall would be enough if -trigraphs was turned on by default, or if
> trigrahs where syntax errors by default.  My problem is that code
> _silently_ compiles differently on gcc with standard options and on an
> ISO C compiler.  This is very different from normal gcc extensions,
> where the code won't compile at all on an ISO C compilers - then one
> certainly notices the difference.

OK, I'll prepare a patch for 3.4 where -Wtrigraphs is on by default.
However, if there are complaints I will revert it to -Wall only, since
that is the long-standing behaviour.

Neil.