[Patch, fortran] Rename gfc_code's expr4 field

[Steve Kargl]

On Wed, Aug 05, 2015 at 08:54:21PM +0200, Mikael Morin wrote:
> 
> this renames the expr4 field of gfc_code to the more descriptive 
> ext.lock.acquired_lock.
> Regression tested on x86_64-unkown-linux-gnu.  OK for trunk?
> 

I don't have a problem with a name change.

> +    /* LOCK/UNLOCK statements  */
> +    struct
> +    {
> +      gfc_expr *acquired_lock;
> +    }
> +    lock;

Just curious.  Why add a struct with a single member?
I would have thought s/expr4/acquired_lock should suffice.

-- 
Steve