Fixes following warnings:
warning: comparison is always false due to limited range of data type

Index: src/wavpack_local.h
================================================================================
--- src/wavpack_local.h
+++ src/wavpack_local.h
@@ -585,7 +585,7 @@
 signed char store_weight (int weight);
 int restore_weight (signed char weight);
 
-#define WORD_EOF (1L << 31)
+#define WORD_EOF ((int32_t)(1L << 31))
 
 // float.c