Fix hard coded aditional c++11 flag

cmake/compiler_settings.cmake

@@ -15,7 +15,7 @@ if(CMAKE_CXX_COMPILER MATCHES icpc)
 endif()
 if (CMAKE_CXX_COMPILER_ID MATCHES Clang)
     set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-isystem")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Werror")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Werror")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=${ARCH}")
     if(CMAKE_BUILD_TYPE MATCHES profile)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -O0  -fprofile-arcs -ftest-coverage")
@@ -24,7 +24,7 @@ endif ()
 if (CMAKE_COMPILER_IS_GNUCXX)
     ## -Wl,--no-as-needed avoids linker problem with libfftwf3 on ubuntu systems
     set(CMAKE_INCLUDE_SYSTEM_FLAG_CXX "-isystem")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} --std=c++11 -pthread -Werror")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pthread -Werror")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wcast-align")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -march=${ARCH}")
     if(CMAKE_BUILD_TYPE MATCHES profile)