SDL_wasapi.c: fixed build against older SDKs.
diff --git a/src/audio/wasapi/SDL_wasapi.c b/src/audio/wasapi/SDL_wasapi.c
index f0c1ac0..c53d9f3 100644
--- a/src/audio/wasapi/SDL_wasapi.c
+++ b/src/audio/wasapi/SDL_wasapi.c
@@ -34,10 +34,16 @@
#include "SDL_wasapi.h"
-/* This constant isn't available on MinGW-w64 */
+/* These constants aren't available in older SDKs */
#ifndef AUDCLNT_STREAMFLAGS_RATEADJUST
#define AUDCLNT_STREAMFLAGS_RATEADJUST 0x00100000
#endif
+#ifndef AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY
+#define AUDCLNT_STREAMFLAGS_SRC_DEFAULT_QUALITY 0x08000000
+#endif
+#ifndef AUDCLNT_STREAMFLAGS_AUTOCONVERTPCM
+#define AUDCLNT_STREAMFLAGS_AUTOCONVERTPCM 0x80000000
+#endif
/* these increment as default devices change. Opened default devices pick up changes in their threads. */
SDL_atomic_t WASAPI_DefaultPlaybackGeneration;