Change-Id: I156b5b16bbd93817ed1f1ad975c1a1dbdfb520f0
Signed-off-by: Nshuaiyutao <shuaiyutao1@huawei.com>

Limit read() and write() requests to sizes that fit in an int.
This allows storing the return value in an int, and avoiding the
need to use or construct an ssize_t type. This is required for
Microsoft C, whose _read and _write functions take an unsigned
request and return an int.

Normally these are set to size_t and ssize_t. But if they do not
exist, then they are set to the smallest integer type that can
contain a pointer. size_t is unsigned and ssize_t is signed.

To build, simply run configure from the source directory by
specifying its path.  That path will be used to find the source
files.  The source directory will not be touched.  All new and
modified files will be made in the current directory.  Discovered
in the process that not all makes understand % or $<, and not all
compilers understand -include or -I-.  This required a larger
Makefile.in with explicit dependencies.

That didn't work when cross-compiling.  Simply rely on limits.h.
If a compiler does not have limits.h, then zconf.h.in should be
modified to define Z_U4 as an unsiged four-byte integer type in
order for crc32() to be fast.

This also simplifies and makes more portable to check for a four-
byte type using limits.h.

This patch allows zlib to compile cleanly with the -Wcast-qual gcc
warning enabled, but only if ZLIB_CONST is defined, which adds
const to next_in and msg in z_stream and in the in_func prototype.
A --const option is added to ./configure which adds -DZLIB_CONST
to the compile flags, and adds -Wcast-qual to the compile flags
when ZLIBGCCWARN is set in the environment.

There were two problems before that this fixes.  One was that the
check for the compiler error return code preceded the determination
of the compiler and its options.  The other was that the checks
for compiler and library characteristics could be fooled if the
error options were set to reject K&R-style C.  configure now aborts
if the compiler produces a hard error on K&R-style C.

In addition, aborts of configure are now consistent, and remove
any temporary files.

The original change was to always use /usr/bin/libtool on Darwin,
in order to avoid using a GNU libtool installed by the user in the
path ahead of Apple's libtool.  However someone might install a
more recent Apple libtool ahead of /usr/bin/libtool.  This commit
checks to see if libtool is Apple, and uses /usr/bin/libtool if it
isn't.

crc_table is made using a four-byte integer (when that can be
determined).  However get_crc_table() returned a pointer to an
unsigned long, which could be eight bytes.  This fixes that by
creating a new z_crc_t type for the crc_table.

This type is also used for the BYFOUR crc calculations that depend
on a four-byte type.  The four-byte type can now be determined by
./configure, which also solves a problem where ./configure --solo
would never use BYFOUR.  No the Z_U4 #define indicates that four-
byte integer was found either by ./configure or by zconf.h.

SunOS 4.1 claims that it is __STDC__, but it does not have strerror
in string.h.  Instead of using __STDC__, this puts a direct test
for strerror in configure, and uses that information in gzguts.h.

Apple removed support for gcov in the default gcc compiler chain,
when they moved to llvm.  This can be circumvented in XCode 4.2 by
using the gcc chain with gcc-4.2.  This patch allows setting
GCC_CLASSIC to the name of a real gcc executable (e.g. "gcc-4.2")
to allow coverage testing.

Previously ./configure would use any output on stderr as an indication
that the compilation failed.  However if some compiler wrapper uses
stderr for some other purpose, e.g. distcc for nodes going down, then
./configure would not properly configure the build.  This problem was
noted by Mike Frysinger.  For backwards compatibility, ./configure
will revert to the old way, i.e. checking for anything on stderr, if
when it deliberately runs the compiler with an error, a zero exit
status is returned.

Adds ARFLAGS variable for options, where AR is now just the command
name.  So now $(AR) $(ARFLAGS) is used to build the static library.

This adds the -fprofile-arcs and -ftest-coverage options when compiling
the source code for the static library.  Those same options must then be
used when linking the static library into an executable.  This updates
Makefile.in to remove and .gitignore to ignore the files generated when
testing coverage.

A common request has been the ability to compile zlib to require no
other libraries.  This --solo option provides that ability.  The price
is that the gz*, compress*, and uncompress functions are eliminated,
and that the user must provide memory allocation and free routines to
deflate and inflate when initializing.