make check_no_exec() work reliable

[Peter Beutner]

Peter Beutner wrote:
> Before starting to make this whole noexecute override behaviour configurable,
> it first must work reliable. In its current form there is no guarantee that
> the check_no_exec() function is actually called, because any other installed
> exception handler might decide to handle the exception itself.
> And as seen by the number of failing applications, this seems to happen
> quite a lot.
> This patch therefore makes check_no_exec() to be called before any other
> exception handler.
> 
> ---
Any comments what is wrong with this one?