Sync zlib sources with GCC, upgrading to 1.2.10.

Changes in 1.2.10 (2 Jan 2017)
- Avoid warnings on snprintf() return value
- Fix bug in deflate_stored() for zero-length input
- Fix bug in gzwrite.c that produced corrupt gzip files
- Remove files to be installed before copying them in Makefile.in
- Add warnings when compiling with assembler code

Changes in 1.2.9 (31 Dec 2016)
- Fix contrib/minizip to permit unzipping with desktop API [Zouzou]
- Improve contrib/blast to return unused bytes
- Assure that gzoffset() is correct when appending
- Improve compress() and uncompress() to support large lengths
- Fix bug in test/example.c where error code not saved
- Remedy Coverity warning [Randers-Pehrson]
- Improve speed of gzprintf() in transparent mode
- Fix inflateInit2() bug when windowBits is 16 or 32
- Change DEBUG macro to ZLIB_DEBUG
- Avoid uninitialized access by gzclose_w()
- Allow building zlib outside of the source directory
- Fix bug that accepted invalid zlib header when windowBits is zero
- Fix gzseek() problem on MinGW due to buggy _lseeki64 there
- Loop on write() calls in gzwrite.c in case of non-blocking I/O
- Add --warn (-w) option to ./configure for more compiler warnings
- Reject a window size of 256 bytes if not using the zlib wrapper
- Fix bug when level 0 used with Z_HUFFMAN or Z_RLE
- Add --debug (-d) option to ./configure to define ZLIB_DEBUG
- Fix bugs in creating a very large gzip header
- Add uncompress2() function, which returns the input size used
- Assure that deflateParams() will not switch functions mid-block
- Dramatically speed up deflation for level 0 (storing)
- Add gzfread(), duplicating the interface of fread()
- Add gzfwrite(), duplicating the interface of fwrite()
- Add deflateGetDictionary() function
- Use snprintf() for later versions of Microsoft C
- Fix *Init macros to use z_ prefix when requested
- Replace as400 with os400 for OS/400 support [Monnerat]
- Add crc32_z() and adler32_z() functions with size_t lengths
- Update Visual Studio project files [AraHaan]

zlib/zutil.h

@@ -1,5 +1,5 @@
 /* zutil.h -- internal interface and configuration of the compression library
- * Copyright (C) 1995-2013 Jean-loup Gailly.
+ * Copyright (C) 1995-2016 Jean-loup Gailly, Mark Adler
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
@@ -36,7 +36,9 @@
 #ifndef local
 #  define local static
 #endif
-/* compile with -Dlocal if your debugger can't find static symbols */
+/* since "static" is used to mean two completely different things in C, we
+   define "local" for the non-static meaning of "static", for readability
+   (compile with -Dlocal if your debugger can't find static symbols) */
 
 typedef unsigned char  uch;
 typedef uch FAR uchf;
@@ -98,28 +100,38 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #endif
 
 #ifdef AMIGA
-#  define OS_CODE  0x01
+#  define OS_CODE  1
 #endif
 
 #if defined(VAXC) || defined(VMS)
-#  define OS_CODE  0x02
+#  define OS_CODE  2
 #  define F_OPEN(name, mode) \
      fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
 #endif
 
+#ifdef __370__
+#  if __TARGET_LIB__ < 0x20000000
+#    define OS_CODE 4
+#  elif __TARGET_LIB__ < 0x40000000
+#    define OS_CODE 11
+#  else
+#    define OS_CODE 8
+#  endif
+#endif
+
 #if defined(ATARI) || defined(atarist)
-#  define OS_CODE  0x05
+#  define OS_CODE  5
 #endif
 
 #ifdef OS2
-#  define OS_CODE  0x06
+#  define OS_CODE  6
 #  if defined(M_I86) && !defined(Z_SOLO)
 #    include <malloc.h>
 #  endif
 #endif
 
 #if defined(MACOS) || defined(TARGET_OS_MAC)
-#  define OS_CODE  0x07
+#  define OS_CODE  7
 #  ifndef Z_SOLO
 #    if defined(__MWERKS__) && __dest_os != __be_os && __dest_os != __win32_os
 #      include <unix.h> /* for fdopen */
@@ -131,18 +143,24 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #  endif
 #endif
 
-#ifdef TOPS20
-#  define OS_CODE  0x0a
+#ifdef __acorn
+#  define OS_CODE 13
 #endif
 
-#ifdef WIN32
-#  ifndef __CYGWIN__  /* Cygwin is Unix, not Win32 */
-#    define OS_CODE  0x0b
-#  endif
+#if defined(WIN32) && !defined(__CYGWIN__)
+#  define OS_CODE  10
 #endif
 
-#ifdef __50SERIES /* Prime/PRIMOS */
-#  define OS_CODE  0x0f
+#ifdef _BEOS_
+#  define OS_CODE  16
+#endif
+
+#ifdef __TOS_OS400__
+#  define OS_CODE 18
+#endif
+
+#ifdef __APPLE__
+#  define OS_CODE 19
 #endif
 
 #if defined(_BEOS_) || defined(RISCOS)
@@ -177,7 +195,7 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
         /* common defaults */
 
 #ifndef OS_CODE
-#  define OS_CODE  0x03  /* assume Unix */
+#  define OS_CODE  3     /* assume Unix */
 #endif
 
 #ifndef F_OPEN
@@ -216,7 +234,7 @@ extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
 #endif
 
 /* Diagnostic functions */
-#ifdef DEBUG
+#ifdef ZLIB_DEBUG
 #  include <stdio.h>
    extern int ZLIB_INTERNAL z_verbose;
    extern void ZLIB_INTERNAL z_error OF((char *m));