Lots of fixes importing SDL source wholesale into a new iOS project

--HG--
rename : src/libm/math.h => src/libm/math_libm.h

src/audio/paudio/SDL_paudio.c

@@ -20,6 +20,8 @@
 */
 #include "SDL_config.h"
 
+#if SDL_AUDIO_DRIVER_PAUDIO
+
 /* Allow access to a raw mixing buffer */
 
 #include <errno.h>
@@ -545,4 +547,6 @@ AudioBootStrap PAUDIO_bootstrap = {
     "paud", "AIX Paudio", PAUDIO_Init, 0
 };
 
+#endif /* SDL_AUDIO_DRIVER_PAUDIO */
+
 /* vi: set ts=4 sw=4 expandtab: */