[C PATCH] Warn for _Alignas + main (PR c/61077)

[Joseph S. Myers]

On Thu, 8 May 2014, Marek Polacek wrote:

> Joseph pointed out that we don't warn when the return type of
> main or the parameter type of main have the _Atomic qualifier.
> This patch adds such warning.
> 
> Regtested/bootstrapped on x86_64-linux, ok for trunk?

OK.

-- 
Joseph S. Myers
joseph@codesourcery.com