Set make.conf package-wise and fix media-video/x264-encoder-0.0.20190903::gentoo

[Axilot]

After applying the LTO patches and recompiling everything the package "media-video/x264-encoder-0.0.20190903" won't compile, because of a configuration error:

ERROR: media-video/x264-encoder-0.0.20190903::gentoo failed (configure phase):
patch -p1  failed with /var/lib/layman/lto-overlay/sys-config/ltoize/files/patches/media-video/x264-encoder-0.0.20190903/lto.patch

After trying to modify the patch and failing, I came to the conclusion, that it may have to do with something else. After reading the "Debugging" section of this Github Wiki, I was wondering how I would be able to save those modifications on a per-package basis, so I would still benefit from every features on most of the packages. And my last question would be, if there is a better way, to get media-video/x264-encoder working. If someone had the same issue, I would really enjoy a helpful responsive.

Best regards, Axilot