Intel: Fix compiler version detection for 2021
Update Classic compiler version detection for 2021. The value of the __INTEL_COMPILER
macro changed convention.
Add a special case for ifx 2021.1 to recognize it as IntelLLVM. The ifx beta versions forgot to define __INTEL_LLVM_COMPILER
, and instead define __INTEL_COMPILER == 201900
. Add a special case.
Fixes: #22120 (closed)
Backport: release
Edited by Brad King