[ccache] gcc -pipe support

[Andrew Tridgell]

Rafal,

 > In theory this fix can inprove speed of ccache becouse md4 calculation
 > is make parallel with pre-compiler but I don't test this aspect. (if
 > someone could make some tests I will be happy)

I think you'll need to demonstate a significant performance
improvement for this to be worthwhile. Adding complexity without a
significant gain is not what we want. I am quite skeptical that this
will gain much at all, but I'm happy to be proven wrong.

Cheers, Tridge

PS: you didn't include the patch