Check if gcc version is already installed on MacOS

[rikardn]

This should resolve #129. I haven't tested it yet.

[rikardn]

This didn't work and I don't fully understand why not. The installed version seems to be 14, but brew then claims to have 12.4.0. Perhaps multiple versions can be installed at the same time.

+++ brew list --versions gcc
+++ cut '-d ' -f2-
+++ cut -d. -f1
++ maj=14
++ '[' 14 == 12 ']'
++ brew install --force gcc@12
Warning: gcc@12 12.4.0 is already installed and up-to-date.
To reinstall 12.4.0, run:
  brew reinstall gcc@12

[rikardn]

My next attempt didn't work either. Need to login to the runner to see what is going on.