Update zconf.h and gzio.c with changes from ZLib 1.2.1 to ZLib 1.2.2.

These are two of the three files that have non-trivial differences from
the vendor branch.  minigzip.c is the third, but there were no changes
from ZLib 1.2.1 to ZLib 1.2.2 in that file.

The rest of the files I intend to get reverted back to the vendor
branch (with cooperation of cvsadmin@).

PR:		i386/76294

2 files changed, 53 insertions, 40 deletions

diff --git a/lib/libz/gzio.c b/lib/libz/gzio.c
index 88e3f03..5424de0 100644
--- a/lib/libz/gzio.c
+++ b/lib/libz/gzio.c
@@ -456,6 +456,10 @@ int ZEXPORT gzread (file, buf, len)
                     s->z_err = Z_ERRNO;
                     break;
                 }
+                if (feof(s->file)) {        /* avoid error for empty file */
+                    s->z_err = Z_STREAM_END;
+                    break;
+                }
             }
             s->stream.next_in = s->inbuf;
         }
diff --git a/lib/libz/zconf.h b/lib/libz/zconf.h
index f3d8467..66e929d 100644
--- a/lib/libz/zconf.h
+++ b/lib/libz/zconf.h
@@ -1,5 +1,5 @@
 /* zconf.h -- configuration of the zlib compression library
- * Copyright (C) 1995-2003 Jean-loup Gailly.
+ * Copyright (C) 1995-2004 Jean-loup Gailly.
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -13,43 +13,46 @@
  * compile with -DZ_PREFIX. The "standard" zlib should be compiled without it.
  */
 #ifdef Z_PREFIX
-#  define deflateInit_  z_deflateInit_
-#  define deflate       z_deflate
-#  define deflateEnd    z_deflateEnd
-#  define inflateInit_  z_inflateInit_
-#  define inflate       z_inflate
-#  define inflateEnd    z_inflateEnd
-#  define deflateInit2_ z_deflateInit2_
-#  define deflateSetDictionary z_deflateSetDictionary
-#  define deflateCopy   z_deflateCopy
-#  define deflateReset  z_deflateReset
-#  define deflatePrime  z_deflatePrime
-#  define deflateParams z_deflateParams
-#  define deflateBound  z_deflateBound
-#  define inflateInit2_ z_inflateInit2_
-#  define inflateSetDictionary z_inflateSetDictionary
-#  define inflateSync   z_inflateSync
-#  define inflateSyncPoint z_inflateSyncPoint
-#  define inflateCopy   z_inflateCopy
-#  define inflateReset  z_inflateReset
-#  define compress      z_compress
-#  define compress2     z_compress2
-#  define compressBound z_compressBound
-#  define uncompress    z_uncompress
-#  define adler32       z_adler32
-#  define crc32         z_crc32
-#  define get_crc_table z_get_crc_table
+#  define deflateInit_          z_deflateInit_
+#  define deflate               z_deflate
+#  define deflateEnd            z_deflateEnd
+#  define inflateInit_          z_inflateInit_
+#  define inflate               z_inflate
+#  define inflateEnd            z_inflateEnd
+#  define deflateInit2_         z_deflateInit2_
+#  define deflateSetDictionary  z_deflateSetDictionary
+#  define deflateCopy           z_deflateCopy
+#  define deflateReset          z_deflateReset
+#  define deflateParams         z_deflateParams
+#  define deflateBound          z_deflateBound
+#  define deflatePrime          z_deflatePrime
+#  define inflateInit2_         z_inflateInit2_
+#  define inflateSetDictionary  z_inflateSetDictionary
+#  define inflateSync           z_inflateSync
+#  define inflateSyncPoint      z_inflateSyncPoint
+#  define inflateCopy           z_inflateCopy
+#  define inflateReset          z_inflateReset
+#  define inflateBack           z_inflateBack
+#  define inflateBackEnd        z_inflateBackEnd
+#  define compress              z_compress
+#  define compress2             z_compress2
+#  define compressBound         z_compressBound
+#  define uncompress            z_uncompress
+#  define adler32               z_adler32
+#  define crc32                 z_crc32
+#  define get_crc_table         z_get_crc_table
+#  define zError                z_zError
 
-#  define Byte          z_Byte
-#  define uInt          z_uInt
-#  define uLong         z_uLong
-#  define Bytef         z_Bytef
-#  define charf         z_charf
-#  define intf          z_intf
-#  define uIntf         z_uIntf
-#  define uLongf        z_uLongf
-#  define voidpf        z_voidpf
-#  define voidp         z_voidp
+#  define Byte                  z_Byte
+#  define uInt                  z_uInt
+#  define uLong                 z_uLong
+#  define Bytef                 z_Bytef
+#  define charf                 z_charf
+#  define intf                  z_intf
+#  define uIntf                 z_uIntf
+#  define uLongf                z_uLongf
+#  define voidpf                z_voidpf
+#  define voidp                 z_voidp
 #endif
 
 #if defined(__MSDOS__) && !defined(MSDOS)
@@ -281,7 +284,7 @@ typedef uLong FAR uLongf;
 #  ifdef VMS
 #    include <unixio.h>   /* for off_t */
 #  endif
-#  define z_off_t  off_t
+#  define z_off_t off_t
 #endif
 #ifndef SEEK_SET
 #  define SEEK_SET        0       /* Seek from beginning of file.  */
@@ -292,11 +295,17 @@ typedef uLong FAR uLongf;
 /*
  * This is hard-configured for FreeBSD, since zlib doesn't actually support
  * using the system off_t for offsets unless off_t is no longer than long.
+ * To minimize the diff, we just "undef z_off_t" rather than modifying
+ * the following lines.
  */
-#define z_off_t long
+#undef z_off_t
+
+#ifndef z_off_t
+#  define z_off_t long
+#endif
 
 #if defined(__OS400__)
-#define NO_vsnprintf
+#  define NO_vsnprintf
 #endif
 
 #if defined(__MVS__)