[ccache] direct mode

[Andrew Stubbs]

On 23/10/13 16:27, Ian Norton wrote:
>  > This scheme does not allow for the case where the compiler's search
> path has been changed, but the "gcc" binary has not, but it should
> certainly catch the cases where the include directories have been
> updated, or the user's own -I include paths have new content.
>
> Is it even possible to change the search paths without a rebuild?

Yes, you can modify the default specs file. (Actually, the default specs 
are built into the gcc binary, but gcc will automatically loads specs 
from a file in the right spot, if you create one.)

>  > In terms of false negatives, it's hard to tell the difference between
> "" and <> includes (in which the search path starts in a different
> place), and it'll be suboptimal where the user's source contains
> explicit paths to header files.
>
> I would hole that statting missing would be quite inexpensive

Hope? Yes, that's my expectation, but any syscall is more expensive than 
not having it.

Andre