Add some missing supplement macros for MIDI support

They are used but not defined for missing OSS support.

libtdemid/sndcard.h

@@ -63,6 +63,8 @@
 #define MIDI_PITCH_BEND 0xE0
 #define MIDI_SYSTEM_PREFIX 0xF0
 #define CTL_MAIN_VOLUME 7
+#define CTL_EXT_EFF_DEPTH 0x50
+#define CTL_CHORUS_DEPTH 0x5D
 
 #define SEQ_DEFINEBUF(a)
 #define SEQ_USE_EXTBUF()