[ccache] Support for color diagnostics

[Lubos Lunak]

On Wednesday 12 of February 2014, Ryan Hill wrote:
> On Fri, 29 Nov 2013 12:39:25 +0100
>
> Lubos Lunak <l.lunak at centrum.cz> wrote:
> >  Clang automatically uses colors for output automatically if used in
> > terminal. Ccache's redirecting to a file disables this. GCC 4.8 has got a
> > similar support, except that it apparently requires also $GCC_COLORS or
> > an explicit option.
> >
> >  The patch detects if the compiler would use colors if used without
> > ccache and explicitly forces an option to achieve this. Note that I do
> > not have GCC 4.8 here, so I tested with Clang's alias and the GCC_COLORS
> > support is done based on documentation.
>
> -fdiagnostics-color and GCC_COLORS were added in 4.9.  Maybe some distros
> have backported it?

 You're right, it's new in 4.9 . But it doesn't actually matter for the patch, 
as it is referenced only in a comment and the commit message.

-- 
 Lubos Lunak