Error loading shared library libgcc_s.so.1 with Ruby 3.1 builds for musl platforms

[mudge]

My latest build with oxidize-rb/actions/cross-gem@v1 has started failing (despite no underlying code changes) but only on Ruby 3.1 and the two musl platforms: aarch64-linux-musl and x86_64-linux-musl, see:

• https://github.com/mudge/rb-mrml/actions/runs/12763551157/job/35574052353
• https://github.com/mudge/rb-mrml/actions/runs/12763551157/job/35574059345

<internal:/usr/local/lib/ruby/3.1.0/rubygems/core_ext/kernel_require.rb>:85:in `require': Error loading shared library libgcc_s.so.1: No such file or directory (needed by /usr/local/bundle/gems/rb-mrml-0.1.0-x86_64-linux-musl/lib/mrml/3.1/mrml.so) - /usr/local/bundle/gems/rb-mrml-0.1.0-x86_64-linux-musl/lib/mrml/3.1/mrml.so (LoadError)

The test runs for the same Ruby version and platform combination from yesterday succeeded:

• https://github.com/mudge/rb-mrml/actions/runs/12744760382/job/35517475832
• https://github.com/mudge/rb-mrml/actions/runs/12744760382/job/35517460617

It looks like cross-gem is still using rb_sys 0.9.107 but my library is now picking up the new 0.9.108.

[mudge]

Note also that the Ruby 3.1 Alpine image was changed recently, see docker-library/ruby#493