diff --git a/third_party/zlib/deflate.c b/third_party/zlib/deflate.c
index 6969577..7c95b30 100644
--- a/third_party/zlib/deflate.c
+++ b/third_party/zlib/deflate.c
@@ -70,14 +70,15 @@ typedef enum {
     finish_done     /* finish done, accept no more input or output */
 } block_state;
 
-typedef block_state (*compress_func) OF((deflate_state *s, int flush));
+typedef block_state (*compress_func) OF((deflate_state *s, int flush,
+                                         int clas));
 /* Compression function. Returns the block state after the call. */
 
 local void fill_window    OF((deflate_state *s));
-local block_state deflate_stored OF((deflate_state *s, int flush));
-local block_state deflate_fast   OF((deflate_state *s, int flush));
+local block_state deflate_stored OF((deflate_state *s, int flush, int clas));
+local block_state deflate_fast   OF((deflate_state *s, int flush, int clas));
 #ifndef FASTEST
-local block_state deflate_slow   OF((deflate_state *s, int flush));
+local block_state deflate_slow   OF((deflate_state *s, int flush, int clas));
 #endif
 local block_state deflate_rle    OF((deflate_state *s, int flush));
 local block_state deflate_huff   OF((deflate_state *s, int flush));
@@ -87,9 +88,9 @@ local void flush_pending  OF((z_streamp strm));
 local int read_buf        OF((z_streamp strm, Bytef *buf, unsigned size));
 #ifdef ASMV
       void match_init OF((void)); /* asm code initialization */
-      uInt longest_match  OF((deflate_state *s, IPos cur_match));
+      uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
 #else
-local uInt longest_match  OF((deflate_state *s, IPos cur_match));
+local uInt longest_match  OF((deflate_state *s, IPos cur_match, int clas));
 #endif
 
 #ifdef DEBUG
@@ -293,6 +294,9 @@ int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
     s->prev   = (Posf *)  ZALLOC(strm, s->w_size, sizeof(Pos));
     s->head   = (Posf *)  ZALLOC(strm, s->hash_size, sizeof(Pos));
+    s->class_bitmap = NULL;
+    zmemzero(&s->cookie_locations, sizeof(s->cookie_locations));
+    strm->clas = 0;
 
     s->high_water = 0;      /* nothing written to s->window yet */
 
@@ -406,6 +410,8 @@ int ZEXPORT deflateResetKeep (strm)
     s = (deflate_state *)strm->state;
     s->pending = 0;
     s->pending_out = s->pending_buf;
+    TRY_FREE(strm, s->class_bitmap);
+    s->class_bitmap = NULL;
 
     if (s->wrap < 0) {
         s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
@@ -900,9 +906,26 @@ int ZEXPORT deflate (strm, flush)
         (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
         block_state bstate;
 
-        bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
-                    (s->strategy == Z_RLE ? deflate_rle(s, flush) :
-                        (*(configuration_table[s->level].func))(s, flush));
+        if (strm->clas && s->class_bitmap == NULL) {
+            /* This is the first time that we have seen alternative class
+             * data. All data up till this point has been standard class. */
+            s->class_bitmap = (Bytef*) ZALLOC(strm, s->w_size/4, sizeof(Byte));
+            zmemzero(s->class_bitmap, s->w_size/4);
+        }
+
+        if (strm->clas && s->strategy == Z_RLE) {
+            /* We haven't patched deflate_rle. */
+            ERR_RETURN(strm, Z_BUF_ERROR);
+        }
+
+        if (s->strategy == Z_HUFFMAN_ONLY) {
+            bstate = deflate_huff(s, flush);
+        } else if (s->strategy == Z_RLE) {
+            bstate = deflate_rle(s, flush);
+        } else {
+            bstate = (*(configuration_table[s->level].func))
+                (s, flush, strm->clas);
+        }
 
         if (bstate == finish_started || bstate == finish_done) {
             s->status = FINISH_STATE;
@@ -999,6 +1022,7 @@ int ZEXPORT deflateEnd (strm)
     TRY_FREE(strm, strm->state->head);
     TRY_FREE(strm, strm->state->prev);
     TRY_FREE(strm, strm->state->window);
+    TRY_FREE(strm, strm->state->class_bitmap);
 
     ZFREE(strm, strm->state);
     strm->state = Z_NULL;
@@ -1131,6 +1155,57 @@ local void lm_init (s)
 #endif
 }
 
+/* class_set sets bits [offset,offset+len) in s->class_bitmap to either 1 (if
+ * class != 0) or 0 (otherwise). */
+local void class_set(s, offset, len, clas)
+    deflate_state *s;
+    IPos offset;
+    uInt len;
+    int clas;
+{
+    IPos byte = offset >> 3;
+    IPos bit = offset & 7;
+    Bytef class_byte_value = clas ? 0xff : 0x00;
+    Bytef class_bit_value = clas ? 1 : 0;
+    static const Bytef mask[8] = {0xfe, 0xfd, 0xfb, 0xf7,
+                                  0xef, 0xdf, 0xbf, 0x7f};
+
+    if (bit) {
+        while (len) {
+            s->class_bitmap[byte] &= mask[bit];
+            s->class_bitmap[byte] |= class_bit_value << bit;
+            bit++;
+            len--;
+            if (bit == 8) {
+                bit = 0;
+                byte++;
+                break;
+            }
+        }
+    }
+
+    while (len >= 8) {
+        s->class_bitmap[byte++] = class_byte_value;
+        len -= 8;
+    }
+
+    while (len) {
+            s->class_bitmap[byte] &= mask[bit];
+            s->class_bitmap[byte] |= class_bit_value << bit;
+            bit++;
+            len--;
+    }
+}
+
+local int class_at(s, window_offset)
+    deflate_state *s;
+    IPos window_offset;
+{
+    IPos byte = window_offset >> 3;
+    IPos bit = window_offset & 7;
+    return (s->class_bitmap[byte] >> bit) & 1;
+}
+
 #ifndef FASTEST
 /* ===========================================================================
  * Set match_start to the longest match starting at the given string and
@@ -1145,9 +1220,10 @@ local void lm_init (s)
 /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
  * match.S. The code will be functionally equivalent.
  */
-local uInt longest_match(s, cur_match)
+local uInt longest_match(s, cur_match, clas)
     deflate_state *s;
     IPos cur_match;                             /* current match */
+    int clas;
 {
     unsigned chain_length = s->max_chain_length;/* max hash chain length */
     register Bytef *scan = s->window + s->strstart; /* current string */
@@ -1195,6 +1271,9 @@ local uInt longest_match(s, cur_match)
     do {
         Assert(cur_match < s->strstart, "no future");
         match = s->window + cur_match;
+        /* If the matched data is in the wrong class, skip it. */
+        if (s->class_bitmap && class_at(s, cur_match) != clas)
+            continue;
 
         /* Skip to next match if the match length cannot increase
          * or if the match length is less than 2.  Note that the checks below
@@ -1237,6 +1316,8 @@ local uInt longest_match(s, cur_match)
         len = (MAX_MATCH - 1) - (int)(strend-scan);
         scan = strend - (MAX_MATCH-1);
 
+#error "UNALIGNED_OK hasn't been patched."
+
 #else /* UNALIGNED_OK */
 
         if (match[best_len]   != scan_end  ||
@@ -1253,15 +1334,23 @@ local uInt longest_match(s, cur_match)
         scan += 2, match++;
         Assert(*scan == *match, "match[2]?");
 
-        /* We check for insufficient lookahead only every 8th comparison;
-         * the 256th check will be made at strstart+258.
-         */
-        do {
-        } while (*++scan == *++match && *++scan == *++match &&
-                 *++scan == *++match && *++scan == *++match &&
-                 *++scan == *++match && *++scan == *++match &&
-                 *++scan == *++match && *++scan == *++match &&
-                 scan < strend);
+        if (!s->class_bitmap) {
+            /* We check for insufficient lookahead only every 8th comparison;
+             * the 256th check will be made at strstart+258.
+             */
+            do {
+            } while (*++scan == *++match && *++scan == *++match &&
+                     *++scan == *++match && *++scan == *++match &&
+                     *++scan == *++match && *++scan == *++match &&
+                     *++scan == *++match && *++scan == *++match &&
+                     scan < strend);
+        } else {
+            /* We have to be mindful of the class of the data and not stray. */
+            do {
+            } while (*++scan == *++match &&
+                     class_at(s, match - s->window) == clas &&
+                     scan < strend);
+        }
 
         Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
 
@@ -1289,20 +1378,74 @@ local uInt longest_match(s, cur_match)
 }
 #endif /* ASMV */
 
+/* cookie_match is a replacement for longest_match in the case of cookie data.
+ * Here we only wish to match the entire value so trying the partial matches in
+ * longest_match is both wasteful and often fails to find the correct match.
+ *
+ * So we take the djb2 hash of the cookie and look up the last position for a
+ * match in a special hash table. */
+local uInt cookie_match(s, start, len)
+    deflate_state *s;
+    IPos start;
+    unsigned len;
+{
+    unsigned hash = 5381;
+    Bytef *str = s->window + start;
+    unsigned i;
+    IPos cookie_location;
+
+    if (len >= MAX_MATCH || len == 0)
+        return 0;
+
+    for (i = 0; i < len; i++)
+        hash = ((hash << 5) + hash) + str[i];
+
+    hash &= Z_COOKIE_HASH_MASK;
+    cookie_location = s->cookie_locations[hash];
+    s->cookie_locations[hash] = start;
+    s->match_start = 0;
+    if (cookie_location &&
+        (start - cookie_location) > len &&
+        (start - cookie_location) < MAX_DIST(s) &&
+        len <= s->lookahead) {
+        for (i = 0; i < len; i++) {
+            if (s->window[start+i] != s->window[cookie_location+i] ||
+                class_at(s, cookie_location+i) != 1) {
+                return 0;
+            }
+        }
+        /* Check that we aren't matching a prefix of another cookie by ensuring
+         * that the final byte is either a semicolon (which cannot appear in a
+         * cookie value), or non-cookie data. */
+        if (s->window[cookie_location+len-1] != ';' &&
+            class_at(s, cookie_location+len) != 0) {
+          return 0;
+        }
+        s->match_start = cookie_location;
+        return len;
+    }
+
+    return 0;
+}
+
+
 #else /* FASTEST */
 
 /* ---------------------------------------------------------------------------
  * Optimized version for FASTEST only
  */
-local uInt longest_match(s, cur_match)
+local uInt longest_match(s, cur_match, clas)
     deflate_state *s;
     IPos cur_match;                             /* current match */
+    int clas;
 {
     register Bytef *scan = s->window + s->strstart; /* current string */
     register Bytef *match;                       /* matched string */
     register int len;                           /* length of current match */
     register Bytef *strend = s->window + s->strstart + MAX_MATCH;
 
+#error "This code not patched"
+
     /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
      * It is easy to get rid of this optimization if necessary.
      */
@@ -1447,6 +1590,20 @@ local void fill_window(s)
                  */
             } while (--n);
 #endif
+            for (n = 0; n < Z_COOKIE_HASH_SIZE; n++) {
+                if (s->cookie_locations[n] > wsize) {
+                    s->cookie_locations[n] -= wsize;
+                } else {
+                    s->cookie_locations[n] = 0;
+                }
+            }
+
+            if (s->class_bitmap) {
+                zmemcpy(s->class_bitmap, s->class_bitmap + s->w_size/8,
+                        s->w_size/8);
+                zmemzero(s->class_bitmap + s->w_size/8, s->w_size/8);
+            }
+
             more += wsize;
         }
         if (s->strm->avail_in == 0) break;
@@ -1465,6 +1622,9 @@ local void fill_window(s)
         Assert(more >= 2, "more < 2");
 
         n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
+        if (s->class_bitmap != NULL) {
+            class_set(s, s->strstart + s->lookahead, n, s->strm->clas);
+        }
         s->lookahead += n;
 
         /* Initialize the hash value now that we have some input: */
@@ -1561,9 +1721,10 @@ local void fill_window(s)
  * NOTE: this function should be optimized to avoid extra copying from
  * window to pending_buf.
  */
-local block_state deflate_stored(s, flush)
+local block_state deflate_stored(s, flush, clas)
     deflate_state *s;
     int flush;
+    int clas;
 {
     /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
      * to pending_buf_size, and each stored block has a 5 byte header:
@@ -1625,13 +1786,19 @@ local block_state deflate_stored(s, flush)
  * new strings in the dictionary only for unmatched strings or for short
  * matches. It is used only for the fast compression options.
  */
-local block_state deflate_fast(s, flush)
+local block_state deflate_fast(s, flush, clas)
     deflate_state *s;
     int flush;
+    int clas;
 {
     IPos hash_head;       /* head of the hash chain */
     int bflush;           /* set if current block must be flushed */
 
+    if (clas != 0) {
+        /* We haven't patched this code for alternative class data. */
+        return Z_BUF_ERROR;
+    }
+
     for (;;) {
         /* Make sure that we always have enough lookahead, except
          * at the end of the input file. We need MAX_MATCH bytes
@@ -1662,7 +1829,7 @@ local block_state deflate_fast(s, flush)
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-            s->match_length = longest_match (s, hash_head);
+            s->match_length = longest_match (s, hash_head, clas);
             /* longest_match() sets match_start */
         }
         if (s->match_length >= MIN_MATCH) {
@@ -1727,12 +1894,25 @@ local block_state deflate_fast(s, flush)
  * evaluation for matches: a match is finally adopted only if there is
  * no better match at the next window position.
  */
-local block_state deflate_slow(s, flush)
+local block_state deflate_slow(s, flush, clas)
     deflate_state *s;
     int flush;
+    int clas;
 {
     IPos hash_head;          /* head of hash chain */
     int bflush;              /* set if current block must be flushed */
+    uInt input_length ;
+    int first = 1;           /* first says whether this is the first iteration
+                                of the loop, below. */
+
+    if (clas == Z_CLASS_COOKIE) {
+        if (s->lookahead) {
+            /* Alternative class data must always be presented at the beginning
+             * of a block. */
+            return Z_BUF_ERROR;
+        }
+        input_length = s->strm->avail_in;
+    }
 
     /* Process the input block. */
     for (;;) {
@@ -1762,13 +1942,18 @@ local block_state deflate_slow(s, flush)
         s->prev_length = s->match_length, s->prev_match = s->match_start;
         s->match_length = MIN_MATCH-1;
 
-        if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
-            s->strstart - hash_head <= MAX_DIST(s)) {
+        if (clas == Z_CLASS_COOKIE && first) {
+            s->match_length = cookie_match(s, s->strstart, input_length);
+        } else if (clas == Z_CLASS_STANDARD &&
+                   hash_head != NIL &&
+                   s->prev_length < s->max_lazy_match &&
+                   s->strstart - hash_head <= MAX_DIST(s)) {
             /* To simplify the code, we prevent matches with the string
              * of window index 0 (in particular we have to avoid a match
              * of the string with itself at the start of the input file).
              */
-            s->match_length = longest_match (s, hash_head);
+            s->match_length = longest_match (s, hash_head, clas);
+
             /* longest_match() sets match_start */
 
             if (s->match_length <= 5 && (s->strategy == Z_FILTERED
@@ -1787,7 +1972,20 @@ local block_state deflate_slow(s, flush)
         /* If there was a match at the previous step and the current
          * match is not better, output the previous match:
          */
-        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
+        first = 0;
+        if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length &&
+            /* We will only accept an exact match for Z_CLASS_COOKIE data and
+             * we won't match Z_CLASS_HUFFMAN_ONLY data at all. */
+            (clas == Z_CLASS_STANDARD || (clas == Z_CLASS_COOKIE &&
+                            s->prev_length == input_length &&
+                            s->prev_match > 0 &&
+                            /* We require that a Z_CLASS_COOKIE match be
+                             * preceded by either a semicolon (which cannot be
+                             * part of a cookie), or non-cookie data. This is
+                             * to prevent a cookie from being a suffix of
+                             * another. */
+                            (class_at(s, s->prev_match-1) == Z_CLASS_STANDARD ||
+                             *(s->window + s->prev_match-1) == ';')))) {
             uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
             /* Do not insert strings in hash table beyond this. */
 
diff --git a/third_party/zlib/deflate.h b/third_party/zlib/deflate.h
index ce0299e..c795034 100644
--- a/third_party/zlib/deflate.h
+++ b/third_party/zlib/deflate.h
@@ -94,6 +94,9 @@ typedef unsigned IPos;
  * save space in the various tables. IPos is used only for parameter passing.
  */
 
+#define Z_COOKIE_HASH_SIZE 256
+#define Z_COOKIE_HASH_MASK (Z_COOKIE_HASH_SIZE-1)
+
 typedef struct internal_state {
     z_streamp strm;      /* pointer back to this zlib stream */
     int   status;        /* as the name implies */
@@ -142,6 +145,8 @@ typedef struct internal_state {
     uInt  hash_mask;      /* hash_size-1 */
 
     uInt  hash_shift;
+    Bytef *class_bitmap;  /* bitmap of class for each byte in window */
+    IPos cookie_locations[Z_COOKIE_HASH_SIZE];
     /* Number of bits by which ins_h must be shifted at each input
      * step. It must be such that after MIN_MATCH steps, the oldest
      * byte no longer takes part in the hash key, that is:
diff --git a/third_party/zlib/zlib.h b/third_party/zlib/zlib.h
index 36c73af..5544c88 100644
--- a/third_party/zlib/zlib.h
+++ b/third_party/zlib/zlib.h
@@ -101,6 +101,7 @@ typedef struct z_stream_s {
     int     data_type;  /* best guess about the data type: binary or text */
     uLong   adler;      /* adler32 value of the uncompressed data */
     uLong   reserved;   /* reserved for future use */
+    int     clas;
 } z_stream;
 
 typedef z_stream FAR *z_streamp;
@@ -207,6 +208,10 @@ typedef gz_header FAR *gz_headerp;
 
 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
 
+#define Z_CLASS_STANDARD 0
+#define Z_CLASS_COOKIE 1
+#define Z_CLASS_HUFFMAN_ONLY 2
+
 #define zlib_version zlibVersion()
 /* for compatibility with versions < 1.0.2 */
 
@@ -1744,6 +1749,13 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file));  /* backward compatibility */
      ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
      ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
      ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
+#  else
+     ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
+     ZEXTERN z_off_t ZEXPORT gzseek OF((gzFile, z_off_t, int));
+     ZEXTERN z_off_t ZEXPORT gztell OF((gzFile));
+     ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
+     ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
+     ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
 #  endif
 #else
    ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
-- 
2.7.4