Add lib{gcc,stdcxx}-ng to ignore_run_exports

[nehaljwani]

Both are statically linked to micromamba:

$ ldd /path/to/micromamba
	linux-vdso.so.1 =>  (0x00007ffe7e544000)
	librt.so.1 => /lib64/librt.so.1 (0x00007f532fdcd000)
	libdl.so.2 => /lib64/libdl.so.2 (0x00007f532fbc9000)
	libresolv.so.2 => /lib64/libresolv.so.2 (0x00007f532f9af000)
	libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f532f792000)
	libm.so.6 => /lib64/libm.so.6 (0x00007f532f50e000)
	libc.so.6 => /lib64/libc.so.6 (0x00007f532f17a000)
	/lib64/ld-linux-x86-64.so.2 (0x00007f5330a99000)

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.

[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.

[nehaljwani]

Not sure what's going on with osx-arm64!

[isuruf]

@conda-forge-admin, rerender

[nehaljwani]

Hmm... so the conda-build version used by me was old. I wonder if conda-smithy should complain about it!

[nehaljwani]

@conda-forge-admin restart ci

[nehaljwani]

msys2/MSYS2-packages#2171 😢

[wolfv]

Don't we need a similar thing for OS X? Happy to merge btw, and thnaks for the contribution!

[nehaljwani]

There is, but it is kinda ugly:
https://github.com/AnacondaRecipes/bazel-feedstock/blob/154e5b02453f9abaea2ac25d32199bc5e1d63bdc/recipe/custom_clang_toolchain/CROSSTOOL.template#L34-L41

[wolfv]

ah, I was pretty confident that statically linking is working on OS X, too. I meant to ignore a potential run_exports from libstdcxx on OS X (or whatever the c++ stdlib on OS X is called, would have to look it up).

[isuruf]

No need to statically link libc++.a. You can interchange system one and conda one as long as you don't do -D_LIBCPP_DISABLE_AVAILABILITY

[nehaljwani]

That's true, but some day (I wish!), one will be using clang on all platforms instead of 3 different compilers for all platforms and would like to have a binary which doesn't link anything except glibc libs 😜 (on linux)

[wolfv]

ah, good to know @isuruf. I was actually thinking of using this flag so that I can use the std::filesystem instead of our current polyfill ...