added protection : MT incompatible with Static allocation

lib/zstd.h

@@ -68,7 +68,7 @@ ZSTDLIB_API unsigned ZSTD_versionNumber(void);   /**< to be used when checking d
 #define ZSTD_QUOTE(str) #str
 #define ZSTD_EXPAND_AND_QUOTE(str) ZSTD_QUOTE(str)
 #define ZSTD_VERSION_STRING ZSTD_EXPAND_AND_QUOTE(ZSTD_LIB_VERSION)
-ZSTDLIB_API const char* ZSTD_versionString(void);
+ZSTDLIB_API const char* ZSTD_versionString(void);   /* v1.3.0 */
 
 
 /***************************************
@@ -424,6 +424,7 @@ typedef struct { ZSTD_allocFunction customAlloc; ZSTD_freeFunction customFree; v
 /* use this constant to defer to stdlib's functions */
 static const ZSTD_customMem ZSTD_defaultCMem = { NULL, NULL, NULL};
 
+
 /***************************************
 *  Frame size functions
 ***************************************/