set '-fopenmp' as compile option too

CMakeLists.txt

@@ -63,6 +63,7 @@ if ( ${CMAKE_CXX_COMPILER_ID} STREQUAL "Intel" )
     add_compile_options ("-diag-disable 383")
     add_compile_options ("-diag-disable 981")
     if (ENABLE_OpenMP)
+        add_compile_options (-openmp)
         add_link_options (-openmp)
     endif ()
 
@@ -77,6 +78,7 @@ elseif (${CMAKE_CXX_COMPILER_ID} MATCHES "Clang")
     # Allow overloaded virtual functions (instances to be fixed in OPAL)
     #add_compile_options (-Wno-overloaded-virtual)
     if (ENABLE_OpenMP)
+        add_compile_options (-fopenmp)
         add_link_options (-fopenmp)
     endif ()
     # Not 100% clear why we need this. But without we get warning while
@@ -90,6 +92,7 @@ elseif (${CMAKE_CXX_COMPILER_ID} MATCHES "GNU")
     # Warning flags
 
     if (ENABLE_OpenMP)
+        add_compile_options (-fopenmp)
         add_link_options (-fopenmp)
     endif ()