[PATCH] Do not error for no_sanitize attributes (PR sanitizer/82490).

[Jakub Jelinek]

On Wed, Oct 11, 2017 at 08:24:28AM +0200, Martin Liška wrote:
> Hi.
> 
> This changes error to a warning:
> warning: ‘foobar’ attribute directive ignored [-Wattributes]
> 
> Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

What is the rationale for not warning?  LLVM compatibility?
I think in some cases it would be nice to find out that I wrote a typo...

> --- /dev/null
> +++ b/gcc/testsuite/c-c++-common/ubsan/attrib-5.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-fsanitize=undefined" } */
> +
> +__attribute__((no_sanitize(("foobar"))))

Too many ()s around the no_sanitize argument.

	Jakub