Do we still need this mutex?

[h-vetinari]

Since conda-forge/ctng-compilers-feedstock#148, conda-forge now switched back from the old libgcc-ng name to the even older original libgcc (AFAIU). This was before my time, so I don't know the details, but the following stood out to me

_libgcc_mutex-feedstock/recipe/meta.yaml

Line 23 in 660e977

summary: 'Mutex for libgcc and libgcc-ng'

It sounds like it wasn't possible then to mix libgcc and libgcc-ng, but looking at

_libgcc_mutex-feedstock/recipe/conda_build_config.yaml

Lines 1 to 4 in 660e977

	libgcc_mutex_build_string:
	- main
	- free
	- conda_forge

it actually seems to be more of a inter-channel question, rather than something within conda-forge itself.

As such, I think we can remove this package from being depended on in our compilers etc.

Thoughts @conda-forge/_libgcc_mutex ?

Edit: Hm, github doesn't seem to want to ping the feedstock here... CC @beckermr @isuruf