Add extern "C" protection to opus_multistream.h.
Unlike the other headers, opus_multistream.h didn't declare
itself to be C code, causing confusing errors when the caller
tries to use the functions from C++.
diff --git a/include/opus_multistream.h b/include/opus_multistream.h
index 24c524e..e6562a7 100644
--- a/include/opus_multistream.h
+++ b/include/opus_multistream.h
@@ -35,6 +35,10 @@
#include "opus.h"
+#ifdef __cplusplus
+extern "C" {
+#endif
+
typedef struct OpusMSEncoder OpusMSEncoder;
typedef struct OpusMSDecoder OpusMSDecoder;
@@ -161,4 +165,8 @@
/** Deallocate a multistream decoder state object */
OPUS_EXPORT void opus_multistream_decoder_destroy(OpusMSDecoder *st);
+#ifdef __cplusplus
+}
+#endif
+
#endif /* OPUS_MULTISTREAM_H */