All compile errors on Mac fixed.

src/sound/i_music.cpp

@@ -40,7 +40,6 @@
 #include <signal.h>
 #include <unistd.h>
 #include "mus2midi.h"
-extern void ChildSigHandler (int signum);
 #endif
 
 #include <ctype.h>
@@ -159,9 +158,6 @@ void I_InitMusic (void)
 		setatterm = true;
 		atterm (I_ShutdownMusicExit);
 	
-#ifndef _WIN32
-		signal (SIGCHLD, ChildSigHandler);
-#endif
 	}
 	MusicDown = false;
 }

src/sound/i_soundfont.cpp

@@ -37,6 +37,10 @@
 #include <stdio.h>
 #include "i_soundfont.h"
 #include "cmdlib.h"
+#include "w_wad.h"
+#include "i_system.h"
+#include "gameconfigfile.h"
+#include "resourcefiles/resourcefile.h"
 
 
 //==========================================================================

src/sound/timiditypp/fft4g.cpp

@@ -285,6 +285,9 @@ Appendix :
     w[] and ip[] are compatible with all routines.
 */
 
+#include <math.h>
+
+
 namespace TimidityPlus
 {
 	void makewt(int nw, int *ip, float *w);
@@ -656,7 +659,6 @@ void dfst(int n, float *a, float *t, int *ip, float *w)
 /* -------- initializing routines -------- */
 
 
-#include <math.h>
 
 void makewt(int nw, int *ip, float *w)
 {
@@ -1348,4 +1350,4 @@ void dstsub(int n, float *a, int nc, float *c)
 	a[m] *= c[0];
 }
 
-}
+}