Hi, As suggested by Wojciech Myrda in bug 659486 [1], it would be helpful if sys-fs/e2fsprogs would use the linux-info eclass to warn if the kernel configuration doesn't include CONFIG_EXT4_FS_SECURITY=y when the user has expressed a desire to use file capabilities. This idea can be extended to any ebuild that provides an mkfs.* program. Thoughts?
[1] https://bugs.gentoo.org/659486#c11 -- Thanks, Zac