Make libmikmod optional since the port isn't working yet.

Makefile

@@ -19,7 +19,7 @@ OBJDIR = ./obj
 BINDIR = ./bin
 TOOLSDIR = ./tools
 
-LINK_FLAGS = -O1 -L$(ROOTDIR)/lib -L$(ROOTDIR)/mips64-elf/lib -ldragon -lmikmod -lmad -lyaml -lc -lm -ldragonsys -lnosys $(LIBS) -Tn64.ld
+LINK_FLAGS = -O1 -L$(ROOTDIR)/lib -L$(ROOTDIR)/mips64-elf/lib -ldragon -lmad -lyaml -lc -lm -ldragonsys -lnosys $(LIBS) -Tn64.ld
 PROG_NAME = OS64
 CFLAGS = -std=gnu99 -march=vr4300 -mtune=vr4300 -O1 -I$(INCDIR) -I$(ROOTDIR)/include -I$(ROOTDIR)/mips64-elf/include -lpthread -lrt -D_REENTRANT -DUSE_TRUETYPE $(SET_DEBUG)
 ASFLAGS = -mtune=vr4300 -march=vr4300

src/sound.c

@@ -3,6 +3,30 @@
 // See LICENSE file in the project root for full license information.
 //
 
+#if !defined(SOUND_ENABLED)
+
+void sndInit(void)
+{
+}
+
+void sndPlayBGM(char* filename)
+{
+}
+
+void sndStopAll(void)
+{
+}
+
+void sndPlaySFX(char* filename)
+{
+}
+
+void sndUpdate(void)
+{
+}
+
+#else
+
 #include <mikmod.h>
 #include <libdragon.h> //needed for audio_get_frequency()
 #include "hashtable.h"
@@ -111,3 +135,4 @@ void sndUpdate(void)
 
     }
 }
+#endif