[OpenBIOS] build warnings on gcc6

[Segher Boessenkool]

On Sun, Mar 06, 2016 at 05:19:07PM +0000, Mark Cave-Ayland wrote:
> > Just because a warning is issued by the compiler doesn't mean the OpenBIOS binary is broken. Werror is used to halt building if the compiler issues a warning. This patch removes Werror so building can continue after such a warning.
> 
> That may be true, but the compiler is trying to tell us something here.
> The worst case scenario is that we may need to disable one specific
> warning if it really is unavoidable, but blanket disabling of Werror is
> not the correct solution here.

You really need some way to disable it then, though.

> Regardless of the outcome, the first thing to do here is to analyse the
> warnings and determine if they are genuine before even considering a patch.

The -Wunused-const-variable warning is correct.  The -Wnonnull-compare
warning may be, I'd have to look at surrounding code.  There are known
problems with this warning.  In general, don't modify your code just to
shut up pre-release compiler versions, not without analysing the issue
first (and please tell us about false positives!)


Segher