Identifying the fuzzing builds in the version string

src/opus.c

@@ -55,5 +55,9 @@ const char *opus_strerror(int error)
 
 const char *opus_get_version_string(void)
 {
-	return "libopus " OPUS_VERSION;
+	return "libopus " OPUS_VERSION
+#ifdef FUZZING
+	      "-fuzzing"
+#endif
+	      ;
 }