Created attachment 719421 [details] emerge --info as required While upgrading blender I was not able successfully build the embree dependency. I was however able to successfully build =media-libs/embree-3.12.2::waebbl. I will attach both build logs and environment for anyone that might be interested in investigating why embree-3.13.0 in the main gentoo tree is broken.
I have not been able to upload the build logs. I keep getting errors. Will try again later. Anyway interested on working on this can also contact me directly for the logs and environments.
One difference that might be relevant is that media-libs/embree-3.13.0::gentoo sets -DEMBREE_IGNORE_CMAKE_CXX_FLAGS=OFF whereas media-libs/embree-3.12.2::waebbl does not. As noted in the ebuild, -march=* flags in CXXFLAGS are problematic for media-libs/embree. Maybe so are other -mfoo (-mmmx, -msse, ...) flags. Try getting rid your CXXFLAGS of them.
These settings were generated using one of Gentoo's optimization tools. I gave it a try, and it compiled when I removed all of the -m* compiler flags. It also worked when I I commented out the line "-DEMBREE_IGNORE_CMAKE_CXX_FLAGS=OFF". I also set "CONFIG_TRANSPARENT_HUGEPAGE" in my kernel (which embree warned me about needing). For the moment I made the comment and built everything. Since I am not a blender specialist I will not know any odd effects might be. That said if I will report back if I find that things break or seems to work. Marking as resolved.
Thanks for the pointers BTW