Standardize NO_CCACHE flag and ccache definitions

[RW]

On Wed, 18 Jun 2008 18:26:14 +0300
Alex Kozlov <spam at rm-rf.kiev.ua> wrote:

> On Wed, Jun 18, 2008 at 05:05:42PM +0200, Alex Dupre wrote:
> > Alex Kozlov ha scritto:
> > > Don't use it for building ports. Actualy it's not necessary even
> > > for make buildworld.
> > 
> > It's necessary if you don't want to use ccache only for 1% of the 
> > buildworld process.
> I use CCACHE_NOHASH_SIZE_MTIME:
> 
> if (getenv("CCACHE_HASH_COMPILER")) {
>     hash_file(args->argv[0]);
> } else if (!getenv("CCACHE_NOHASH_SIZE_MTIME")) {
>     hash_int(st.st_size);
>     hash_int(st.st_mtime);
> }
> 

I'm not sure what your point is here.  

CCACHE_HASH_COMPILER is by far the more conservative of the two. I use
CCACHE_HASH_COMPILER all the time, it hasn't caused any problems. The
cost of hashing the compiler driver is negilible.

If you don't set either then each time you rebuild world you
invalidate most of your cache.