Fix mangled function names.

third_party/zlib/zlib.h

Index: third_party/zlib/zlib.h
===================================================================
--- third_party/zlib/zlib.h	(revision 116430)
+++ third_party/zlib/zlib.h	(working copy)
@@ -1572,12 +1572,14 @@
 #endif
 
 #if !defined(ZLIB_INTERNAL) && _FILE_OFFSET_BITS-0 == 64 && _LFS64_LARGEFILE-0
-#  define gzopen gzopen64
-#  define gzseek gzseek64
-#  define gztell gztell64
-#  define gzoffset gzoffset64
-#  define adler32_combine adler32_combine64
-#  define crc32_combine crc32_combine64
+#  if !defined(MOZZCONF_H)
+#    define gzopen gzopen64
+#    define gzseek gzseek64
+#    define gztell gztell64
+#    define gzoffset gzoffset64
+#    define adler32_combine adler32_combine64
+#    define crc32_combine crc32_combine64
+#  endif
 #  ifdef _LARGEFILE64_SOURCE
      ZEXTERN gzFile ZEXPORT gzopen64 OF((const char *, const char *));
      ZEXTERN z_off_t ZEXPORT gzseek64 OF((gzFile, z_off_t, int));