[CFT] Buildworld ccache support

[Bryan Drewery]

> On Oct 15, 2015, at 17:31, Warren Block <wblock at wonkity.com> wrote:
> 
>> 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?

No but I could likely adapt it for there too. I'm more cautious about putting this there since I never build stable.

Bryan