Fix KERNEL_INFO_RE

[dezza]

Polyphony fails to build if uname -sr is not formed a certain way, since $KERNEL_INFO_RE does not match on some systems.

Current regex requires:

• 3 digits
• word at the end

Other samples I found:

• Linux 5.10.60.1-microsoft-standard-WSL2 (Windows Subsystem for Linux), includes - in word.
• Linux 5.10.63+ (raspbian), no word present

I propose: Linux (\d)\.(\d+)(?:\.)?((?:\d+\.?)*)(?:\-)?([\w\-]+)?

Which will match on: Linux 5.10.63.62.63, infinite patch numbers Linux 5.10.60.1-microsoft-standard-WSL2, word at the end including -

This should ensure

• Remaining revision/patch-version is always in group 3
• Distribution is always in group 4
• Both groups are optional

Test: https://regex101.com/r/CLX00x/1

[dezza]

~Out of curiosity, why did you close the PR? This seems like a valuable change.~ Nevermind, I now see your other PR #89.

Yeah.. On afterthought, maybe it would be wiser to drop the regex and do

kernel_info = `uname -r`
version_str, distribution = kernel_info.split('-')
version, major_revision = version_str.split('.')