Sandbox issue with ccache 4.6
Users with ccache enabled for the dev-util/ccache package itself may need to temporarily disable ccache in order to upgrade the package.
Users on an earlier version of ccache (<4.6) or newer (>=4.6-r1) are unaffected.
For a small window (between 2022-04-09-4:30AM UTC and 2022-04-09-11:27AM UTC), the ccache ebuild may have caused a sandbox violation  in some circumstances.
To resolve this issue, temporarily re-emerge dev-util/ccache with ccache disabled: # FEATURES="-ccache" emerge -v1 ">dev-util/ccache-4.6"
The sandbox violations occur when trying to use ccache for any package; users who do not have ccache enabled globally (or at least not for ccache itself) should also proactively upgrade ccache as above.