Add mixed clang/gfortran build with cmake on OSX

azure-pipelines.yml

@@ -122,6 +122,22 @@ jobs:
       make
       ctest
       
+- job: OSX_OpenMP_Clang_gf_cmake
+  pool:
+     vmImage: 'macOS-10.15'
+  variables:
+     LD_LIBRARY_PATH: /usr/local/opt/llvm/lib
+     LIBRARY_PATH: /usr/local/opt/llvm/lib
+  steps:   
+  - script: |
+      brew update
+      brew install llvm libomp
+      mkdir build
+      cd build
+      cmake -DTARGET=CORE2 -DUSE_OPENMP=1 -DINTERFACE64=1 -DDYNAMIC_ARCH=1 -DCMAKE_C_COMPILER=/usr/local/opt/llvm/bin/clang -DNO_AVX512=1 ..
+      make
+      ctest
+        
 - job: OSX_Ifort_Clang
   pool:
      vmImage: 'macOS-10.15'