wasapi: try to satisfy both mingw and msvc
Fix-up for previous commit, hopefully.
diff --git a/sys/wasapi/gstwasapiutil.c b/sys/wasapi/gstwasapiutil.c
index c689f50..5563ee7 100644
--- a/sys/wasapi/gstwasapiutil.c
+++ b/sys/wasapi/gstwasapiutil.c
@@ -32,6 +32,7 @@
#if defined(_MSC_VER)
#include <functiondiscoverykeys_devpkey.h>
#elif !defined(PKEY_Device_FriendlyName)
+#include <initguid.h>
#include <propkey.h>
DEFINE_PROPERTYKEY (PKEY_Device_FriendlyName, 0xa45c254e, 0xdf1c, 0x4efd, 0x80,
0x20, 0x67, 0xd1, 0x46, 0xa8, 0x50, 0xe0, 14);