Seeing udev does not support fprefetch-loop-array it should be filters instead of constantly spamming screen about and unsupported CFLAG. Exact info being spewed : warning: -fprefetch-loop-arrays is not supported with -Os
Have a patch for the ebuild to do this?
Created attachment 65708 [details, diff] filter flags that are not supported Sorry ment to get the patch up sooner but here it is against latest version.
patch is avaliable
Fixed in 068 release, thanks for the patch.