Patch cleanup

[izahn]

Checklist

• Used a personal fork of the feedstock to propose changes
• Bumped the build number (if the version is unchanged)
• Reset the build number to 0 (if the version changed)
• Re-rendered with the latest conda-smithy (Use the phrase @conda-forge-admin, please rerender in a comment in this PR for automated rerendering)
• Ensured the license file is being packaged.

Closes #161

This is partly a conversation starter, but mostly serious. Do we really need all those patches? The other R packaging efforts I've looked at (e.b., https://formulae.brew.sh/formula/r and https://github.com/archlinux/svntogit-packages/blob/packages/r/trunk/PKGBUILD) appear not to do any patching at all.

[conda-forge-linter]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe) and found it was in an excellent condition.

[izahn]

As far as I can tell this looks pretty good. I don't understand the osx_arm64 failure at all -- what is supposed to happen there?

[xhochy]

I'm -1 on deleting all of them. Most of the things seem to work without them but some of the patches that adjust link flags probably don't have an impact on the tests executed in the test: section of the recipe but e.g. handle whether the libgcc symbols should be statically linked or not.

[izahn]

Right, I don't expect that we will end up dropping all patches. But each one imposes a maintenance burden, and it will simplify things if we can drop all but those we really need. My assessment is that most of the patches we've been maintaining here are trivial and can be dropped without consequence; most of the rest are better suited for contributing to upstream. My hope is that this PR will serve as a starting point for re-evaluating what we really want to maintain.

[mingwandroid]

I am in favour of removing any of my patches that can be proven unneeded by adding an (ideally) run-time test to the package to make sure the removal of the patch doesn't regress the issue it is meant to resolve.

[mingwandroid]

Some of the early patches I have I did intend to try to upstream a long time ago. @opencpu, what is your take on moving the Windows R build to work properly via autotools? Would upstream go for that? Would you like it?

[izahn]

Thanks all for engaging with this, I'll try to find time to do a more thorough assessment of each patch and get a better handle on what needs to be maintained. This can be a longer-term project, no need to hold up the 4.0.4 update for it.