check the Intel compiler for thread_local

cmake/Modules/ClhepVariables.cmake

@@ -261,6 +261,8 @@ macro( clhep_set_compiler_flags )
     else()
       _clhep_use_pthread()
     endif()
+  elseif( ${CMAKE_CXX_COMPILER_ID} STREQUAL "Intel" )
+    _clhep_use_pthread()
   else()
     set(CLHEP_THREAD_DEFINITION "#define CLHEP_THREAD_LOCAL")
   endif()