Removed unnecessary SDL #include's

src/sound/i_music.cpp

@@ -37,7 +37,6 @@
 #include <windows.h>
 #include <mmsystem.h>
 #else
-#include <SDL.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/stat.h>

src/sound/i_musicinterns.h

@@ -13,7 +13,6 @@
 #include <windows.h>
 #include <mmsystem.h>
 #else
-#include <SDL.h>
 #define FALSE 0
 #define TRUE 1
 #endif

src/tempfiles.h

@@ -38,6 +38,8 @@
 #pragma once
 #endif
 
+#include <stdlib.h>
+
 // Returns a file name suitable for use as a temp file.
 // If you create a file with this name (and presumably you
 // will), it will be deleted automatically by this class's