- Change gnutls pointer/int macros to pointer/curl_socket_t.
  Prior to this change they used long type as well.

The size of the `long` data type can be shorter than that of pointer
types. This is the case most notably on Windows.

If C99 were acceptable, we could simply use `intptr_t` here. But we
want to retain C89 compatibility.

Simply use the trick of performing pointer arithmetic with the NULL
pointer: to convert an integer `i` to a pointer, simply take the
address of the `i`th element of a hypothetical character array
starting at address NULL. To convert back, simply cast the pointer
difference.

Thanks to Jay Satiro for the initial modification to use curl_socket_t
instead of int/long.

Closes #1617

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Bug: #1616
Closes #1633

CURL_STATIC_CRT and ENABLE_INET_PTON

Closes #1621

... to enable tracking down why autobuilds fail on this

Bug: #1616

... and don't build at all in include

Prompted-by-work-by: Simon Warta
Ref: #1590
Closes #1591

As per https://github.com/curl/curl/pull/1615, the DICT server is a
little spammy in torture mode due to the sockets being torn down
unexpectedly. Fix this by adding some error handling to the handling
function.

Closes #1629

Add a new server which provides a DICT interface. This is intended to
begin coverage testing for lib/dict.c

Closes #1615

The test.h file is no longer in the same directory as the source file,
so that directory needs to be added to the include path.

Fixes #1627
Closes #1628

Add a connection check function to HTTP2 based off RTSP. This causes
PINGs to be handled the next time the connection is reused.

Closes #1521

Add a new type of callback to Curl_handler which performs checks on
the connection. Alter RTSP so that it uses this callback to do its
own check on connection health.

Fixes #1620

Prevent `Curl_pgrsTime` from modifying `t_starttransfer` when invoked
with `TIMER_STARTTRANSFER` more than once during a single request.

When a redirect occurs, this is considered a new request and
`t_starttransfer` can be updated to reflect the `t_starttransfer` time
of the redirect request.

Closes #1616

Bug: https://github.com/curl/curl/pull/1602#issuecomment-310267370

Reported-by: Jesse Chisholm

Fixes #1623

Closes https://github.com/curl/curl/pull/1454

If libcurl was built with GSS-API support, it unconditionally advertised
GSS-API authentication while connecting to a SOCKS5 proxy.  This caused
problems in environments with improperly configured Kerberos: a stock
libcurl failed to connect, despite libcurl built without GSS-API
connected fine using username and password.

This commit introduces the CURLOPT_SOCKS5_AUTH option to control the
allowed methods for SOCKS5 authentication at run time.

Note that a new option was preferred over reusing CURLOPT_PROXYAUTH
for compatibility reasons because the set of authentication methods
allowed by default was different for HTTP and SOCKS5 proxies.

Bug: https://curl.haxx.se/mail/lib-2017-01/0005.html
Closes https://github.com/curl/curl/pull/1454

... to make it obvious what the data is used for

... instead of having the generated code checked in. This saves space in
the tarball but primarily automatically adapts to newly added options.

Closes #1614

Bug: https://github.com/curl/curl/pull/1486#issuecomment-310926872
Reported-by: Dan Fandrich

The integer literal 3123123123 doesn't fit into a 32-bit signed
integer, so GCC with 32-bit long warns in C90 mode:
this decimal constant is unsigned only in ISO C90 [enabled by default]
Fix this by using ULONG_MAX, which should fit in any curl_off_t and has
the correct suffix to not issue any warnings.
Also adds the missing CURLOPT_REQUEST_TARGET from commit
9b167fd0.

Closes https://github.com/curl/curl/pull/1611

Reported-by: Neil Kolban
Fixes: 1598

Compile with `WIN32_LEAN_AND_MEAN` which prevents `windows.h` from
including too much clutter including `wincrypt.h` which in turn contains
some preprocessor macros that clash with boringssl symbols.

Detect boringssl by checking the existance of `is_boringssl.h` and set
the corresponding `HAVE_BORINGSSL` for compilation which is used in
`ldap.c` to undefine the evil macros.

Closes #1610

follow-up to 64ed44a8 to fix test 500 failures

Since 5598b0bd, clang -v is used to
detect the clang version. The version number was expected to come after
the word "version". For Apple clang, this doesn't work as it has its
own versioning scheme.
The version number is now first searched after the string
"based on LLVM". This works for Apple clang before version 7, and also
for e.g. Ubuntu's clang up to version 3.7. If it's not found and the
version string contains "Apple LLVM version", clang version 3.7 is
assumed, which is the version that comes with Xcode 7. Otherwise, the
version number is still expected after the word "version", which works
for very old Apple clang versions.

Ref: https://trac.macports.org/wiki/XcodeVersionInfo
Fixes https://github.com/curl/curl/issues/1606
Closes https://github.com/curl/curl/pull/1607

... supported since 7.54.1

To reduce the memory requirement for decompress, and still do almost as
good compression as with -9e.

Pointed-out-by: Dan Fandrich

The compressed output size seems to be a tad bit smaller, but generally
xz seems more preferred these days and is used directly by for example
gentoo instead of bz2.

"Users of LZMA Utils should move to XZ Utils" =>
https://tukaani.org/lzma/

Closes #1604

... and CURLOPT_REQUEST_TARGET instead of CURLOPT_STRIP_PATH_SLASH.

This option instead provides the full "alternative" target to use in the
request, instead of extracting the path from the URL.

Test 1298 and 1299 updated accordingly.

Idea-by: Evert Pot
Suggestion: https://daniel.haxx.se/blog/2017/06/19/options-with-curl/comment-page-1/#comment-18373

Closes #1593

Declare TU-local variables static.

- switch debug and release configurations so that we get an optimized
  build with GCC 4.3+ as required by typecheck-gcc
- enable warnings-as-errors for release builds
  (which have warnings disabled)

Closes https://github.com/curl/curl/pull/1595

typecheck-gcc expected curl_socket_t instead of curl_off_t arguments
for CURLINFO_OFF_T. Detected by test1521, unfortunately only when run
locally.

Closes https://github.com/curl/curl/pull/1592

Bug: https://github.com/curl/curl/commit/73a2fcea0b4adea6ba342cd7ed1149782c214ae3#commitcomment-22655993

remote_scope_id is only used when both HAVE_SOCKADDR_IN6_SIN6_SCOPE_ID
and ENABLE_IPV6 are defined instead of only one of them.