minor refactor

lib/zstd_decompress.c

@@ -75,7 +75,6 @@
 #  pragma warning(disable : 4127)        /* disable: C4127: conditional expression is constant */
 #  pragma warning(disable : 4324)        /* disable: C4324: padded structure */
 #else
-#  define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
 #  ifdef __GNUC__
 #    define FORCE_INLINE static inline __attribute__((always_inline))
 #  else
@@ -276,8 +275,6 @@ void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
       TO DO
 */
 
-static const size_t ZSTD_fcs_fieldSize[4] = { 0, 1, 2, 8 };
-
 /** ZSTD_frameHeaderSize() :
 *   srcSize must be >= ZSTD_frameHeaderSize_min.
 *   @return : size of the Frame Header */