[Chapel Merge] Allow Homebrew LLVM as the default on Darwin syste

Branch: refs/heads/master
Revision: 1acb090
Author: daviditen
Log Message:

Merge pull request #17852 from daviditen/allow-homebrew-llvm-darwin

Allow Homebrew LLVM as the default on Darwin systems

[reviewed by @mppf]

The util/chplenv/chpl_llvm.py script was checking for darwin platform and
disallowing a default of CHPL_LLVM=system in that case. Remove the check so
that if a good Homebrew LLVM is installed we will default to using it.

Signed-off-by: David Iten daviditen@users.noreply.github.com

Modified Files:
M util/chplenv/chpl_llvm.py

Compare: https://github.com/chapel-lang/chapel/compare/3824df28396d...1acb0906c7e4