Reland "Integrate SIMD optimisations for zlib"

third_party/zlib/deflate.h

Index: third_party/zlib/deflate.h
diff --git a/third_party/zlib/deflate.h b/third_party/zlib/deflate.h
index 2fe6fd6670f5f6742655c736d08fd2c89b58dc6c..d15f2b5d58d5bc8053161445b16e46a3a53d79f3 100644
--- a/third_party/zlib/deflate.h
+++ b/third_party/zlib/deflate.h
@@ -107,6 +107,8 @@ typedef struct internal_state {
     Byte  method;        /* STORED (for zip only) or DEFLATED */
     int   last_flush;    /* value of flush param for previous deflate call */
 
+    unsigned zalign(16) crc0[4 * 5];
+
                 /* used by deflate.c: */
 
     uInt  w_size;        /* LZ77 window size (32K by default) */
@@ -344,4 +346,14 @@ void ZLIB_INTERNAL _tr_stored_block OF((deflate_state *s, charf *buf,
               flush = _tr_tally(s, distance, length)
 #endif
 
+/* Functions that are SIMD optimised on x86 */
+void ZLIB_INTERNAL crc_fold_init(deflate_state* const s);
+void ZLIB_INTERNAL crc_fold_copy(deflate_state* const s,
+                                 unsigned char* dst,
+                                 const unsigned char* src,
+                                 long len);
+unsigned ZLIB_INTERNAL crc_fold_512to32(deflate_state* const s);
+
+void ZLIB_INTERNAL fill_window_sse(deflate_state* s);
+
 #endif /* DEFLATE_H */