Part of the hash for ccache files is composed from the real compilers size and mtime. After upgrading gcc, it's more or less certain that these would have changed, and hence the entire ccache is obsolete. This is not immediately obvious to users that aren't experienced with ccache, so it would help if the ebuild informed the user of this fact. Perhaps something along these lines after merging: "After gcc has been merged again, all ccache data will be obsolete. Unless you have taken steps to work around this, you might as well clear the cache with 'ccache -c' to recover disk space." Of course it would only make sense to print this info if ccache is enabled in FEATURES, and ccache is installed, but that should be easy to check for.
i dont really see this being worthwhile
agreed, although down the line *possibly*.
