audio: Don't wrap bootstrap declarations in preprocessor macros.

They are harmless and ignored if we don't actually link against them. The
preprocessor checks elsewhere if they're actually used.

src/audio/SDL_sysaudio.h

@@ -179,77 +179,30 @@ typedef struct AudioBootStrap
     int demand_only;  /* 1==request explicitly, or it won't be available. */
 } AudioBootStrap;
 
-#if SDL_AUDIO_DRIVER_PULSEAUDIO
+/* Not all of these are available in a given build. Use #ifdefs, etc. */
 extern AudioBootStrap PULSEAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_ALSA
 extern AudioBootStrap ALSA_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_SNDIO
 extern AudioBootStrap SNDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_BSD
 extern AudioBootStrap BSD_AUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_OSS
 extern AudioBootStrap DSP_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_QSA
 extern AudioBootStrap QSAAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_SUNAUDIO
 extern AudioBootStrap SUNAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_ARTS
 extern AudioBootStrap ARTS_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_ESD
 extern AudioBootStrap ESD_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_NACL
 extern AudioBootStrap NACLAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_NAS
 extern AudioBootStrap NAS_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_XAUDIO2
 extern AudioBootStrap XAUDIO2_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_DSOUND
 extern AudioBootStrap DSOUND_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_WINMM
 extern AudioBootStrap WINMM_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_PAUDIO
 extern AudioBootStrap PAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_HAIKU
 extern AudioBootStrap HAIKUAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_COREAUDIO
 extern AudioBootStrap COREAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_DISK
 extern AudioBootStrap DISKAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_DUMMY
 extern AudioBootStrap DUMMYAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_FUSIONSOUND
 extern AudioBootStrap FUSIONSOUND_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_ANDROID
 extern AudioBootStrap ANDROIDAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_PSP
 extern AudioBootStrap PSPAUDIO_bootstrap;
-#endif
-#if SDL_AUDIO_DRIVER_EMSCRIPTEN
 extern AudioBootStrap EMSCRIPTENAUDIO_bootstrap;
-#endif
-
-
 
 #endif /* SDL_sysaudio_h_ */