Only enables -fopenmp in case the user wants stxxl

Author: daniel-j-h

CMakeLists.txt

@@ -590,11 +590,13 @@ add_dependency_defines(-DBOOST_SPIRIT_USE_PHOENIX_V3)
 add_dependency_defines(-DBOOST_RESULT_OF_USE_DECLTYPE)
 add_dependency_defines(-DBOOST_FILESYSTEM_NO_DEPRECATED)
 
-set(OpenMP_FIND_QUIETLY ON)
-find_package(OpenMP)
-if(OPENMP_FOUND)
-  message(STATUS "OpenMP support found. Linking just in case for stxxl")
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+if (ENABLE_STXXL)
+  set(OpenMP_FIND_QUIETLY ON)
+  find_package(OpenMP)
+  if(OPENMP_FOUND)
+    message(STATUS "OpenMP support found. Linking just in case for stxxl")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+  endif()
 endif()
 
 add_definitions(${OSRM_DEFINES})