Greg, I am repeatedly building port NCARG with a simple recipe, as part of
my local testing regime. I never use any special options related to a
clang version or OpenMP. This seems to work fine every time. I am on a
Mac Pro, currently running OS 10.14.6 Mojave and Xcode 11.3. This also
worked
Apple’s clang numbering and LLVM’s clang numbering diverged a while ago, and in
fact LLVM’s clang is usually a year or two ahead of Apple’s.
Apple has it’s own fork of clang and llvm, and the two are similar but not
identical. Indeed, openmp support is one area where they diverge.
LLVM’s clang
I'm looking at my dev Mac and there are several versions of "clang" on
the system:
mac{cmbuild}% /usr/bin/clang -v
Apple LLVM version 10.0.1 (clang-1001.0.46.4)
Target: x86_64-apple-darwin18.7.0
Thread model: posix
InstalledDir:
