Hi! get an error compiling :)

[Initial build] Compiling ==> modules\futari\futari_gizmo_modifiers.cpp futari_gizmo_modifiers.cpp modules\futari\futari_gizmo_modifiers.cpp(183): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(184): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(208): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(220): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(266): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(262): error C2660: 'FutariModifierGizmoPlugin::curved_arrow': function does not take 4 arguments modules\futari\futari_gizmo_modifiers.cpp(146): note: see declaration of 'FutariModifierGizmoPlugin::curved_arrow' modules\futari\futari_gizmo_modifiers.cpp(280): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(282): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(290): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(344): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(340): error C2660: 'FutariModifierGizmoPlugin::curved_arrow': function does not take 4 arguments modules\futari\futari_gizmo_modifiers.cpp(146): note: see declaration of 'FutariModifierGizmoPlugin::curved_arrow' modules\futari\futari_gizmo_modifiers.cpp(359): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(363): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(368): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(425): error C2065: 'M_PI': undeclared identifier modules\futari\futari_gizmo_modifiers.cpp(438): error C2065: 'M_PI': undeclared identifier scons: *** [modules\futari\futari_gizmo_modifiers.windows.tools.64.obj] Error 2 scons: building terminated because of errors.

did i screw something up? :(