
STLport was ment for older compilers lacking certain modern instructions like msvc6 its kinda overkill to use it for a modern msvc.
besides that you probably need to configure STLport for msvc 2013, that should take care of the errors.
Just tried and stlport does not build with msvc 2013 so bugger

just try and build without it remember to remove the folder or gtkradiant will still pick it up.