Try to eliminate dead stores (#444)

Signed-off-by: Alexander Shopov <ash@kambanaria.org>
original commit: 84a6a6ab36294c73dbdc617d19c42fada42c3a15

LOG

@@ -1389,3 +1389,5 @@
     expeditor.c
 - prevent access before start of array
     scheme.c
+- remove dead stores in files
+    compress-io.c, new-io.c

c/compress-io.c

@@ -329,7 +329,7 @@ INT S_glzclose(glzFile glz) {
 #ifdef EINTR
           if (r < 0 && errno == EINTR) continue;
 #endif
-	  if (r == 0) { r = Z_ERRNO; saved_errno = errno; }
+	  if (r == 0) { saved_errno = errno; }
           break;
         }
         (void)LZ4F_freeDecompressionContext(lz4->dctx);

c/new-io.c

@@ -842,8 +842,6 @@ ptr S_bytevector_compress(ptr dest_bv, iptr d_start, iptr d_count,
         if (!is_valid_lz4_length(s_count))
           return Sstring("source bytevector ~s is too large");
 
-        destLen = (int)d_count;
-
         destLen = LZ4_compress_default((char *)&BVIT(src_bv, s_start), (char *)&BVIT(dest_bv, d_start), (int)s_count, (int)d_count);
 
         if (destLen > 0)