rubiks: Work around build failure with XCode

[mkoeppe]

On Apple clang version 13.1.6 (clang-1316.0.21.2.5), building g++ -std=gnu++11 -g -O2 -c mcube.cpp appears to hang forever.

We work around this by reducing the optimization level on macOS.

CC: @jhpalmieri

Component: packages: optional

Author: Matthias Koeppe

Branch/Commit: 6b9e1d7

Reviewer: John Palmieri

Issue created by migration from https://trac.sagemath.org/ticket/34293

[mkoeppe]

Branch: u/mkoeppe/rubiks__work_around_build_failure_with_xcode

[mkoeppe]

New commits:

4895341	build/pkgs/rubiks/spkg-install.in: Remove obsolete workaround
6b9e1d7	build/pkgs/rubiks/spkg-install.in: Work around compiler hang with XCode

[mkoeppe]

Commit: 6b9e1d7

[jhpalmieri]

comment:3

Thank you, this works for me. A vaguely related question: after installing rubiks, if I do ./sage -t src/sage/groups/perm_gps/cubegroup.py, then it runs tests marked optional - rubiks, but it says Features detected for doctesting: <blank> at the end. The appropriate "Feature" says that rubiks is present. Why doesn't it list rubiks among the features?

[jhpalmieri]

Reviewer: John Palmieri

[mkoeppe]

comment:4

When rubiks is installed through the Sage distribution, the Sage doctester sees the installation record in local/lib/sage/installed/ and adds rubiks to the optional tags. It does not run the Feature test.

[mkoeppe]

comment:5

See #33823 comment:22 for a more detailed explanation

[vbraun]

Changed branch from u/mkoeppe/rubiks__work_around_build_failure_with_xcode to 6b9e1d7