Added missing define.
diff --git a/include/mmsystem.h b/include/mmsystem.h
index 27119e1..e80271b 100644
--- a/include/mmsystem.h
+++ b/include/mmsystem.h
@@ -1302,6 +1302,7 @@
#define MIXERCONTROL_CONTROLTYPE_MONO (MIXERCONTROL_CONTROLTYPE_BOOLEAN + 3)
#define MIXERCONTROL_CONTROLTYPE_LOUDNESS (MIXERCONTROL_CONTROLTYPE_BOOLEAN + 4)
#define MIXERCONTROL_CONTROLTYPE_STEREOENH (MIXERCONTROL_CONTROLTYPE_BOOLEAN + 5)
+#define MIXERCONTROL_CONTROLTYPE_BASS_BOOST (MIXERCONTROL_CONTROLTYPE_BOOLEAN + 0x00002277)
#define MIXERCONTROL_CONTROLTYPE_BUTTON (MIXERCONTROL_CT_CLASS_SWITCH | MIXERCONTROL_CT_SC_SWITCH_BUTTON | MIXERCONTROL_CT_UNITS_BOOLEAN)
#define MIXERCONTROL_CONTROLTYPE_DECIBELS (MIXERCONTROL_CT_CLASS_NUMBER | MIXERCONTROL_CT_UNITS_DECIBELS)
#define MIXERCONTROL_CONTROLTYPE_SIGNED (MIXERCONTROL_CT_CLASS_NUMBER | MIXERCONTROL_CT_UNITS_SIGNED)