Summary

Add the capability to combine any number of environments together under one view.

Rationale

No response

Description

Entry point
Check for conflicts in existing environments
Print new combined view
Entry point on the concretize command

Example:
spack env combine concretize --name current env1 env2 ... env6 eConf
spack -e current install
generate: current/spack.yaml & current/spack.lock

Additional information

• Spack: 0.19.0.dev0
• Python: 3.7.2
• Platform: linux-rhel7-broadwell
• Concretizer: clingo

General information

• I have run spack --version and reported the version of Spack
• I have searched the issues of this repo and believe this is not a duplicate