Fixed MinGW-w64 build
diff --git a/src/audio/wasapi/SDL_wasapi.c b/src/audio/wasapi/SDL_wasapi.c
index 8079525..b7c8dda 100644
--- a/src/audio/wasapi/SDL_wasapi.c
+++ b/src/audio/wasapi/SDL_wasapi.c
@@ -37,6 +37,11 @@
#include "SDL_wasapi.h"
+/* This constant isn't available on MinGW-w64 */
+#ifndef AUDCLNT_STREAMFLAGS_RATEADJUST
+#define AUDCLNT_STREAMFLAGS_RATEADJUST 0x00100000
+#endif
+
/* these increment as default devices change. Opened default devices pick up changes in their threads. */
SDL_atomic_t WASAPI_DefaultPlaybackGeneration;
SDL_atomic_t WASAPI_DefaultCaptureGeneration;