Disable the usage of CXX11 by default

Created by: tmadlener

BEGINRELEASENOTES

• Disable USE_CXX11 by default since we switched to c++17 quite some time ago and this option needs to be manually disabled in order to make that work via CMAKE_CXX_STANDARD.

ENDRELEASENOTES

cmakemodules/ilcsoft_default_cxx_flags.cmake

@@ -30,7 +30,7 @@ FOREACH( FLAG ${COMPILER_FLAGS} )
   ENDIF()
 ENDFOREACH()
 
-OPTION( USE_CXX11 "Use CXX Standard 2011" True )
+OPTION( USE_CXX11 "Use CXX Standard 2011" OFF )
 IF( USE_CXX11 )
   SET( FLAG "-std=c++11" )
   SET( FLAG_WORD "stdCXX11" )