I like the File System Hierarchy (FHS), but I also enjoy Nix flakes.
Note. This "like" is more than just a useless partiality. I collaborate on projects that assume FHS —— for example, projects that use an install.sh —— meaning that pure NixOS may get in the way.
The FHS thing may be workaroundable with containers, or testing via QEMU, or via patchelf or steam-run or any of the hacks NixOS uses to get by. Negatives notwithstanding, I have reason to believe NixOS may be my future, final distro.
Until then, I use the nix-guix overlay rather than a intra-user installation.
/etc/portage/repos.conf/nix-guix.conf
[nix-guix]
location = /var/db/repos/nix-guix
sync-type = git
sync-uri = https://github.com/trofi/nix-guix-gentoo.git
/etc/portage/package.accept_keywords/overlays
*/*::nix-guix ~amd64
And I use flakes, since they lock better. I didn't bother to read about its controversy.
(nix.conf was configured as per the Nix wiki ⇗)
/etc/nix/nix.conf
experimental-features = nix-command flakes
/etc/portage/package.use/nix
dev-libs/boehm-gc cxx
virtual/libcrypt static-libs
sys-libs/libxcrypt static-libs
/etc/portage/package.accept_keywords/nix
dev-libs/editline ~amd64
dev-libs/libcpuid ~amd64
dev-cpp/toml11 ~amd64
dev-util/cargo-c ~amd64 # avoids slot conflict in 2025-04-30
# because libgit2 should be version 1.9