Silence some warnings from Visual Studio C.

deflate.h

@@ -329,8 +329,8 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
 # define _tr_tally_dist(s, distance, length, flush) \
   { uch len = (uch)(length); \
     ush dist = (ush)(distance); \
-    s->sym_buf[s->sym_next++] = dist; \
-    s->sym_buf[s->sym_next++] = dist >> 8; \
+    s->sym_buf[s->sym_next++] = (uch)dist; \
+    s->sym_buf[s->sym_next++] = (uch)(dist >> 8); \
     s->sym_buf[s->sym_next++] = len; \
     dist--; \
     s->dyn_ltree[_length_code[len]+LITERALS+1].Freq++; \

trees.c

@@ -1017,9 +1017,9 @@ int ZLIB_INTERNAL _tr_tally (s, dist, lc)
     unsigned dist;  /* distance of matched string */
     unsigned lc;    /* match length-MIN_MATCH or unmatched char (if dist==0) */
 {
-    s->sym_buf[s->sym_next++] = dist;
-    s->sym_buf[s->sym_next++] = dist >> 8;
-    s->sym_buf[s->sym_next++] = lc;
+    s->sym_buf[s->sym_next++] = (uch)dist;
+    s->sym_buf[s->sym_next++] = (uch)(dist >> 8);
+    s->sym_buf[s->sym_next++] = (uch)lc;
     if (dist == 0) {
         /* lc is the unmatched char */
         s->dyn_ltree[lc].Freq++;