I was getting ~~~~ src/udev/udev-builtin-btrfs.c:31:8: error: redefinition of ‘struct btrfs_ioctl_vol_args’ ~~~~ with linux-headers-3.7. Updating to 3.13 (latest stable) resolved the issue. (See also http://forums.gentoo.org/viewtopic-p-7594838.html).
Thanks for reporting, this is known problem and specific to 215, it's been taken care of in 216 so it builds again with older headers 216 is also the next stable, have it queue'd for another, more serious bug in 215 already So nothing left to do here really, just watch and see 216 become the stable and 215* vanish after
well whatever, committed the dep anyway... + 02 Sep 2014; Samuli Suominen <ssuominen@gentoo.org> udev-215-r1.ebuild: + Raise linux-headers dependency for 215-r1 because of the file handle struct + patch wrt #521902. This problem is specific to 215-r1, and -r1 only. +
