Some builds fail with invalid gcc flag "-Xarch_x86_64" (Linux+CMake+PCH)

[romildo]

Describe the bug

Building of tdesktop-2.2.0 (Telegram Desktop) on my NixOS unstable system fails with the message:

g++: error: unrecognized command line option '-Xarch_x86_64'; did you mean '-march=x86-64'?

Notify maintainers

@primeos @abbradar

Metadata

• system: "x86_64-linux"
• host os: Linux 5.7.12, NixOS, 20.09.git.4254de4a41f (Nightingale)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.3.7
• channels(root): "nixos-20.09pre237279.8e2b14aceb1"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

Maintainer information:

# a list of nixpkgs attributes affected by the problem
attribute: tdesktop
# a list of nixos modules affected by the problem
module:

[primeos]

Failing Hydra build: https://hydra.nixos.org/build/124793339

This is most likely due to the same problem as in #93761 (comment) and should affect multiple packages.

From the investigation of @orivej it seems to be caused by a recent CMake update (#93886).

[orivej]

Yes, I expect that all CMake packages that use target_precompile_headers are affected. (Very few I suppose, since this feature was added in CMake 3.16.) Currently I'm bisecting CMake.

[primeos]

@orivej I had a quick look at the Git history of CMake and https://gitlab.kitware.com/cmake/cmake/-/commit/f593b354da2e9637e9b869688934f0ba2544ebed?expanded=1#6c9f77aa6e8d69a3b0b3ddcff14fb5312faa7b5a_2457_2469 seems like a good candidate.

Anyway, thanks a lot for investigating this ❤️ :)

[orivej]

Indeed, this is caused by https://gitlab.kitware.com/cmake/cmake/-/merge_requests/4561

[primeos]

So I guess a quick workaround might be to only add the CMAKE_OSX_* variables (especially CMAKE_OSX_ARCHITECTURES) on macOS builds?

And according to https://cmake.org/cmake/help/latest/variable/CMAKE_OSX_ARCHITECTURES.html it should also be a CMake bug as it states:

This variable is ignored on platforms other than Apple.

[orivej]

Yes. I have reported it at https://gitlab.kitware.com/cmake/cmake/-/issues/21072

[primeos]

I've pushed e798793 as a temporary quick-fix for the tdesktop build.

[samuelgrf]

The fix for this issue was just merged into CMake master: https://gitlab.kitware.com/cmake/cmake/-/merge_requests/5118

[doronbehar]

Let's keep this open for anyone else stumbling such issues, until staging is merged to channels.

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/installing-audacity/8575/2