[CFT] Buildworld ccache support

[Warren Block]

On Thu, 15 Oct 2015, Bryan Drewery wrote:

> Hi,
>
> If you are interested in using ccache in buildworld please consider
> using this patch locally and giving me some feedback.  The current
> advice for ccache+buildworld (the CC:= trick in make.conf) actually
> results in the build thinking you are using a cross-compiler which
> results in unintended side-effects.  It also doesn't work with meta mode
> as it handles CC and toolchain differently.  This patch intends to cover
> all cases.
>
> https://people.freebsd.org/~bdrewery/patches/world-ccache.diff
>
> To use just set WITH_CCACHE_BUILD= in src.conf or make.conf.  I
> purposely matched it to the same as the ports build.

Will this work on -stable?