This workarounds old libssh2 versions not properly initializing
some ssh session variables, which would trigger memory debuggers
warnings on memory being used without having been initialized.

The current version of speedcheck.c may disable timeout by setting zero
to Curl_expire. Which is fine using the curl_multi_perform, because it
recheck all timeout internals, but when using custom event poller (like
hiperfifo.c) it may keep stalle connection forever.

Calling sclose() both in the child and the parent fools the
socket leak detector into thinking it's been closed twice.
Calling close() in the child instead overcomes this problem. It's
not as portable as the sclose() macro, but this code is highly
POSIX-specific, anyway.

Just internal stuff...

Curl_safefree is now a macro defined in memdebug.h instead of a function
prototyped in url.h and implemented in url.c, so inclusion of url.h is no
longer required in order to simply use Curl_safefree.

Provide definition of macro WHILE_FALSE in setup_once.h in order to allow
other macros such as DEBUGF and DEBUGASSERT, and code using it, to compile
without 'conditional expression is constant' warnings.

The WHILE_FALSE stuff fixes 150+ MSVC compiler warnings.

Ensure existing logic in Curl_resolv_timeout() is not subverted upon getting a
negative timeout from resolve_server(). The timeout in resolve_server() could
be checked to avoid calling Curl_resolv_timeout() with an expired timeout, but
fixing this in this way allows existing logic in resolve_server() to be kept
unchanged.

follow-up for commit d20408e8

follow-up for commit c06de200

This removes command length restrictions on calling functions.

First:

File curl_ntlm.h renamed curl_ntlm_msgs.h
File curl_ntlm.c renamed curl_ntlm_msgs.c

Afterwards:

File http_ntlm.c renamed curl_ntlm.c
File http_ntlm.h renamed curl_ntlm.h

Configure script option --enable-wb-ntlm-auth renamed to --enable-ntlm-wb
Configure script option --disable-wb-ntlm-auth renamed to --disable-ntlm-wb

Preprocessor symbol WINBIND_NTLM_AUTH_ENABLED renamed to NTLM_WB_ENABLED
Preprocessor symbol WINBIND_NTLM_AUTH_FILE renamed to NTLM_WB_FILE

Test harness env var CURL_NTLM_AUTH renamed to CURL_NTLM_WB_FILE

Static function wb_ntlm_close renamed to ntlm_wb_cleanup
Static function wb_ntlm_initiate renamed to ntlm_wb_init
Static function wb_ntlm_response renamed to ntlm_wb_response

Feature string literal NTLM_SSO renamed to NTLM_WB.
Preprocessor symbol USE_NTLM_SSO renamed to WINBIND_NTLM_AUTH_ENABLED.
curl's 'long' option 'ntlm-sso' renamed to 'ntlm-wb'.
Fix some comments to make clear that this is actually a NTLM delegation.

Functions renamed:

Curl_output_ntlm_sso -> Curl_output_ntlm_wb
sso_ntlm_close -> wb_ntlm_close
sso_ntlm_response -> wb_ntlm_response
sso_ntlm_initiate -> wb_ntlm_initiate

Preprocessor symbols renamed:

CURLAUTH_NTLM_SSO -> CURLAUTH_NTLM_WB
CURL_VERSION_NTLM_SSO -> CURL_VERSION_NTLM_WB

Output of Curl_ntlm_create_type1_message() and Curl_ntlm_create_type3_message()
functions is now already base64 encoded.