Update for alpine linux

[mattfidler]

Match windows reqirements

[mattfidler]

Hi, @bastistician

Let me know if this works for you. If so, I will adapt it for all other work-arounds.

I can submit this to CRAN now, since it has been over 30 days since my last submit with rxode2ll. For the other packages I may have to wait until Dec or next year.

[bastistician]

Thanks for working on this portability issue.
The change in this PR won't work as intended. Makevars.win isn't used on linux.

--------[begin src/Makevars]--------
cat: can't open 'src/Makevars': No such file or directory
--------[end src/Makevars]--------

[mattfidler]

This should work for alpine linux.

[mattfidler]

nlmixr2/rxode2#809
nlmixr2/nlmixr2extra#74
nlmixr2/nlmixr2est#495
nlmixr2/babelmixr2#147

[bastistician]

Ah I see, so -isystem was intended as a workaround for PopOS? It seems -I will now be used everywhere but on that OS. Note that the PRETTY_NAME or NAME info from /etc/os-release is already stored in utils::osVersion, so you could just check that string.

Anyway, I can confirm that the current version of this PR installs and checks fine on Alpine Linux. Thanks!

[mattfidler]

Ah I see, so -isystem was intended as a workaround for PopOS?

No, actually I meant this for all systems that support -isystem; but since I develop on PopOS, I want to use it there at the very least. The -isystem flag suppresses all non rxode2ll system messages that I need to take care of instead of showing the many, many stan math/eigen warnings that make it difficult to figure out what needs to be fixed on my end (with -I).

It also makes the compilation experience a bit easier to digest. But it truly isn't needed otherwise.

So out an abudence of caution, I have disabled it on every platform except the one I develop on 😄

[mattfidler]

Thanks for the suggestion @bastistician, integrated it as suggested.