The code in configure for OpenMP on macOS is incorrect: it assumes Clang with libopm, so the check fails with GCC, where OpenMP is supported in fact. Instead, compiler should be checked first: if GCC is detected, OpenMP should be set to supported, and only Clang needs a test, because it may or may not have libomp.
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The code in configure for OpenMP on macOS is incorrect: it assumes Clang with libopm, so the check fails with GCC, where OpenMP is supported in fact. Instead, compiler should be checked first: if GCC is detected, OpenMP should be set to supported, and only Clang needs a test, because it may or may not have libomp.