cmake: check that USER-INTEL flags actually work

    else()

      set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -xHost")

    endif()

    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -qopenmp -qno-offload -fno-alias -ansi-alias -restrict -DLMP_INTEL_USELRT -DLMP_USE_MKL_RNG -O2 -fp-model fast=2 -no-prec-div -qoverride-limits -qopt-zmm-usage=high")

    include(CheckCXXCompilerFlag)

    foreach(_FLAG -qopenmp -qno-offload -fno-alias -ansi-alias -restrict -DLMP_INTEL_USELRT -DLMP_USE_MKL_RNG -O2 "-fp-model fast=2" -no-prec-div -qoverride-limits -qopt-zmm-usage=high)

      check_cxx_compiler_flag("${__FLAG}" COMPILER_SUPPORTS${_FLAG})

      if(COMPILER_SUPPORTS${_FLAG})

        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${_FLAG}")

      endif()

    endforeach()

    set(USER-INTEL_SOURCES_DIR ${LAMMPS_SOURCE_DIR}/USER-INTEL)

    set(USER-INTEL_SOURCES ${USER-INTEL_SOURCES_DIR}/intel_preprocess.h

                           ${USER-INTEL_SOURCES_DIR}/intel_buffers.h