No WSAGetLastError() on Watt-32/DOS

No <sys/uio.h> on DOS/Win32

Changes for Watt-32 on Windows. I've assumed Configure
sets the required HAVE_xx defines for non-DOS/Win targets.

Alexander Krasnostavsky made the write callback get called even when a zero
byte file is downloaded.

socks proxy and timeouts bug

actually, we check for a numerical host using either ipv4 or ipv6, as neither
should result in a reverse dns lookup

use inet_pton() correctly!

ZLIB_ROOT not needed

My first CVS commit just to see if this works.
BTW. Used eclipse IDE fo this, which really kicks ass.

simplified expression

Ling Thio pointed out that getaddrinfo() reverse-lookups ip-only names, and
this is an attempt to prevent it from doing that. affects ipv6-enabled only.

the autobuilds failed all over on AIX, attempt to fix the strerror_r() problem
by setting _THREAD_SAFE (and -qthreaded) before strerror_r() is checked for.

reuse handles in PHP/CURL works - Kirk Hedden told us

PHP FAQ

indented the code curl-style

removed trailing whitespace

see also the reset function

mention the reset function

Kjetil Jacobsen reported an open file leak in file:// transfers of empty
files.

added a check for the xlc compiler on AIX, and if that is detect we use
the -qthreaded compiler option

define _THREAD_SAFE on (recent) AIX systems to build thread-safe code

recent fixes

allow a custom "Accept-Encoding:" header override the internally set one
that gets set with CURLOPT_ENCODING

strip trailing whitespace

syncronized with libcurl.def.