[ccache] Using a shared ccache in cmake environment (linux)

[Paul Smith]

On Mon, 2020-03-16 at 20:26 +0100, Steffen Dettmer via ccache wrote:
> As workaround for a special unrelated issue currently we redefine
> __FILE__ (and try to remove that redefinition). I understand that
> ccache still works thanks to CCACHE_BASEDIR even for __FILE__ usage
> inside files. Is that correct?

You don't say which compiler you're using but if you're using GCC you
can consider using the -ffile-prefix-map option to avoid these issues.

For clang I think they have the -fmacro-prefix-map and
-fdebug-prefix-map options but not -ffile-prefix-map.