diff -r 668eff08387f -r 675775c33ab6 contrib/python-zstandard/zstd/common/zstd_common.c
--- a/contrib/python-zstandard/zstd/common/zstd_common.c	Thu Apr 04 15:24:03 2019 -0700
+++ b/contrib/python-zstandard/zstd/common/zstd_common.c	Thu Apr 04 17:34:43 2019 -0700
@@ -30,8 +30,10 @@
 /*-****************************************
 *  ZSTD Error Management
 ******************************************/
+#undef ZSTD_isError   /* defined within zstd_internal.h */
 /*! ZSTD_isError() :
- *  tells if a return value is an error code */
+ *  tells if a return value is an error code
+ *  symbol is required for external callers */
 unsigned ZSTD_isError(size_t code) { return ERR_isError(code); }
 
 /*! ZSTD_getErrorName() :