Add FreeBSD clang/gfortran build with OpenMP

.cirrus.yml

@@ -148,6 +148,15 @@ FreeBSD_task:
   - ls -l /usr/local/lib
   - gmake CC=gcc INTERFACE64=1
 
+FreeBSD_task:
+  name: FreeBSD-clang-openmp
+  freebsd_instance:
+    image_family: freebsd-13-2
+  install_script:
+  - pkg update -f && pkg upgrade -y && pkg install -y gmake gcc 
+  compile_script:
+  - gmake CC=clang FC=gfortran USE_OPENMP=1 CPP_THREAD_SAFETY_TEST=1
+
 #task:
 #  name: Windows/LLVM16     --- too slow ---
 #  windows_container: