Based on discussions with the xgboost developers, it appears that only
the C++ library changes based on whether it is built in CPU or GPU mode.
The other language bindings do not change based on whether this
functionality exists or not. So drop all of the per package mutexes to
streamline things a bit.

…nda-forge-pinning 2019.10.22

Now that the per package CPU/GPU mutexes have been dropped, re-render
the feedstock to update its content accordingly.

As only the C++ library changes between CPU and GPU builds, add a meta
package to allow selection between the two builds of the C++ library.
Since this does not include GPU builds yet, simply set the selection
package to CPU only.

…nda-forge-pinning 2019.10.22

Now that `xgboost-proc` has been added for CPU/GPU selection, re-render
to update the feedstock content accordingly.

Rebuild all of the packages now that the CPU/GPU selection metapackages
have been restructured.

…nda-forge-pinning 2023.07.06.05.56.46