Fix compiler warning

Avoid redundant check. configure script takes care of not defining
HAVE_WINDOWS_H, HAVE_WINSOCK_H, HAVE_WINSOCK2_H, neither
HAVE_WS2TCPIP_H when __CYGWIN__ is defined.

Being unable to link or find out recv() or send() args types is a fatal error.

This is now a working example using libevent and curl_multi_socket() for really
fast treatment of many simultaneous transfers

adding CURLM_CALL_MULTI_SOCKET that's just the same as CURLM_CALL_MULTI_PERFORM

MinGW/MSYS needs lib ws2_32 for proper operation of configure script.

Ravi Pratap fixed ares_getsock() to actually return the proper bitmap and
not always zero!

removed running_handles argument from multi_runsingle() since it wasn't really
used anymore since multi->num_alive was introduced

Silence compiler warning 'unused parameter running_handles' in function multi_runsingle(). This is done here returning multi->num_alive in the running_handles parameter even when functions that call

Silence compiler warning 'unused parameter running_handles' in function multi_runsingle(). This is done here returning multi->num_alive in the running_handles parameter even when functions that call multi_runsingle() at this moment overwrite the returned value with the one that is valid when those functions curl_multi_perform() and multi_socket() have removed expired timers from the splay. Most probably, parameter 'running_handles' in function multi_runsingle() should be just removed.

show more ...

keep count of the number of "alive" handles in a struct member, as otherwise
*multi_socket*() can't return the proper number

Mark Lentczner fixed how libcurl was not properly doing chunked encoding
if the header "Transfer-Encoding: chunked" was set by the application.
http://curl.haxx.se/bug/view.cgi?id=1531838

a CURLOPT_PROGRESSFUNCTION clarification

Maciej Karpiuk fixed a crash that would occur if we passed Curl_strerror()
an unknown error number on glibc systems.
http://curl.haxx.se/bug/view.cgi?id=1532289

spell-fixed a comment

updated docs with the new parameter

Avoid the risk of a false positive detection of MSG_NOSIGNAL when cross compiling a Windows target.

Silence warning: empty body in an if-statement

Force compilation failure in case macros sread() or swrite() are not defined.

Provide definitions needed for macros sread() and swrite() in config file.

adapt to the new protos

curl_multi_socket() and curl_multi_socket_all() got modified prototypes: they
both now provide the number of running handles back to the calling function.

Winsock and Cygwin need address family specification before bind(), this should be harmless for others.

Fix compiler warnings.

include setup_once.h dependency and adjust to 80 char lines.

new D binding