The idea behind that is to enable users and developers of
downstream tools such as home-manager to test Nix master for several
reasons:
* Nix is currently trying to have a `master` branch that's always
releasable[1]. We're still on Nix 2.18 in nixpkgs due to too many
notable regressions. Enabling people to test latest master may help on
that end.
* This uses the most bleeding-edge Nix, but our packaging, so we can
identify issues with our packaging early.
* From what I've seen, most people are using the packages from nixpkgs
anyways instead of the upstream flake, this is far more convenient
anyways.
My plan is to update this once a week. Right now we rely on the
`installCheckPhase` here, but as soon as we have proper regression
testing[2], we may want to add `nixUnstable` there as well (however with
failures being allowed probably).
[1] https://discourse.nixos.org/t/nix-release-schedule-and-roadmap/14204
[2] https://github.com/NixOS/nixpkgs/pull/304332
The nixpkgs-unstable channel's programs.sqlite was used to identify
packages producing exactly one binary, and these automatically added
to their package definitions wherever possible.
- merge libcxxabi into libcxx for LLVM 12, 13, 14, 15, 16, 17, and git.
- remove the link time workaround `-lc++ -lc++abi` from 58 packages as it is no longer required.
- fixes https://github.com/NixOS/nixpkgs/issues/166205
- provides alternative fixes for. https://github.com/NixOS/nixpkgs/issues/269548https://github.com/NixOS/nix/issues/9640
- pkgsCross.x86_64-freebsd builds work again
This change can be represented in 3 stages
1. merge libcxxabi into libcxx -- files: pkgs/development/compilers/llvm/[12, git]/{libcxx, libcxxabi}
2. update stdenv to account for merge -- files: stdenv.{adapters, cc.wrapper, darwin}
3. remove all references to libcxxabi outside of llvm (about 58 packages modified)
### merging libcxxabi into libcxx
- take the union of the libcxxabi and libcxx cmake flags
- eliminate the libcxx-headers-only package - it was only needed to break libcxx <-> libcxxabi circular dependency
- libcxx.cxxabi is removed. external cxxabi (freebsd) will symlink headers / libs into libcxx.
- darwin will re-export the libcxxabi symbols into libcxx so linking `-lc++` is sufficient.
- linux/freebsd `libc++.so` is a linker script `LINK(libc++.so.1, -lc++abi)` making `-lc++` sufficient.
- libcxx/default.nix [12, 17] are identical except for patches and `LIBCXX_ADDITIONAL_LIBRARIES` (only used in 16+)
- git/libcxx/defaul.nix does not link with -nostdlib when useLLVM is true so flag is removed. this is not much different than before as libcxxabi used -nostdlib where libcxx did not, so libc was linked in anyway.
### stdenv changes
- darwin bootstrap, remove references to libcxxabi and cxxabi
- cc-wrapper: remove c++ link workaround when libcxx.cxxabi doesn't exist (still exists for LLVM pre 12)
- adapter: update overrideLibcxx to account for a pkgs.stdenv that only has libcxx
### 58 package updates
- remove `NIX_LDFLAGS = "-l${stdenv.cc.libcxx.cxxabi.libName}` as no longer needed
- swift, nodejs_v8 remove libcxxabi references in the clang override
https://github.com/NixOS/nixpkgs/pull/292043
