failure to properly detect recvfrom arg types on Solaris

to the data type pointed by its respective argument and not the pointer type.

finds out its return type and the types of its arguments. Added definitions
for non-configure systems config files, and introduced macro sreadfrom which
will be used on udp sockets as a recvfrom() wrapper.

Configure process no longer needs nor checks size of curl_off_t.
Library will now be built with _REENTRANT symbol defined.

added to DISABLED.

These are included from lib/setup.h or specific source code file.

and lib/setup_once.h

file has been included. In this way if symbol is defined in the config file
it will no longer be ignored.

  doing "proxy-tunnels" with non-HTTP prototols and that was simply because
  the code assumed the user-agent was only needed for HTTP.

uploads with -C - didn't resume properly, but the tests pass.

set the attribute that has changed instead of all possible ones. Hopefully,
this will solve the "Permission denied" problem that Nagarajan Sreenivasan
reported when setting some modes, but regardless, it saves a protocol
round trip in the chmod case.

curl-library list on July 9th 2008 by Mathew Hounsell)

NOTE: the name resolve functions of various libc implementations don't re-read
name server information unless explicitly told so (by for example calling
Ires_init(3). This may cause libcurl to keep using the older server even
if DHCP has updated the server info, and this may look like a DNS cache issue
to the casual libcurl-app user.

is set in fdset.events" (http://curl.haxx.se/bug/view.cgi?id=2015126) which
exactly pinpointed the problem only triggered on Windows Vista, provided
reference to docs and also a fix. There is much work behind Peter Lamberg's
excellent bug report. Thank You!