Error when compiling USER-OMP package

Dear Developers,

I am trying to compile Lammps using Cmake with compilers OpenMPI 4.0 + clang 10
Everything looks run well until compiling …/src/USER-OMP and the error when the compiling stop is as following:

this is documented: https://lammps.sandia.gov/doc/Build_basics.html#default-none-issues
which provides a workaround. a more permanent fix has been proposed but not yet tested and integrated.