A function added to this package ran as part of importing it and
printed a warning for most Spack invocations, this removes the
warning message.
Also:
* Use compilers directly instead of Spack compiler wrappers (since
references to the compiler are embedded in text and binary files
of the installation)
* Add 'cross' variant for setting CROSS environment variable for
build
* Set UPCXX_INSTALL for generated module files
* Set UPCXX_GASNET_CONDUIT/UPCXX_NETWORK in generated module files
on Cray systems
* Also set UPCXX_NETWORK in build environment for Cray systems
7a11a2ccdb