loop-aes prior to 3.7e will not compile on 4.2.x kernels; https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=df6b35f409af0a8ff1ef62f552b8402f3fef8665 renamed i387.h and other modifications as well. At a quick test, loop-aes-3.7e, released on 2015-09-03, builds and works well gentoo-sources-4.2.3, with minor changes to the .ebuild since -3.7c. Reproducible: Always
Created attachment 414630 [details] Adding an ebuild which works for me, with minor changes to loop-aes-3.7e.
in future, please attach diffs. thanks!