In addition to unix domain sockets, Linux also supports an
abstract namespace which is independent of the filesystem.

In order to support it, add new CURLOPT_ABSTRACT_UNIX_SOCKET
option which uses the same storage as CURLOPT_UNIX_SOCKET_PATH
internally, along with a flag to specify abstract socket.

On non-supporting platforms, the abstract address will be
interpreted as an empty string and fail gracefully.

Also add new --abstract-unix-socket tool parameter.

Signed-off-by: Isaac Boukris <iboukris@gmail.com>
Reported-by: Chungtsun Li (typeless)
Reviewed-by: Daniel Stenberg
Reviewed-by: Peter Wu
Closes #1197
Fixes #1061

We have higher resolution since 7.52.0

So that only "global" options (verbose mostly) survive into the next
transfer, and the others have to be set again unless default is fine.

Closes #1169

Assisted-by: Tim Rühsen

It made the german ß get converted to ss, IDNA2003 style, and we can't
have that for the .de TLD - a primary reason for our switch to IDNA2008.

Test 165 verifies.

Follow-up to f30cbcac

Closes #1207

Under condition using http_proxy env var, noproxy list was the
combination of --noproxy option and NO_PROXY env var previously. Since
this commit, --noproxy option overrides NO_PROXY environment variable
even if use http_proxy env var.

Closes #1140

If defined CURL_DISABLE_HTTP, detect_proxy() returned NULL. If not
defined CURL_DISABLE_HTTP, detect_proxy() checked noproxy list.

Thus refactor to set proxy to NULL instead of calling detect_proxy() if
define CURL_DISABLE_HTTP, and refactor to call detect_proxy() if not
define CURL_DISABLE_HTTP and the host is not in the noproxy list.

The combination of --noproxy option and http_proxy env var works well
both for proxied hosts and non-proxied hosts.

However, when combining NO_PROXY env var with --proxy option,
non-proxied hosts are not reachable while proxied host is OK.

This patch allows us to access non-proxied hosts even if using NO_PROXY
env var with --proxy option.

References: http://unicode.org/faq/idn.html
            http://unicode.org/reports/tr46

Closes #1206

Closes #1194

Check for presence of gnutls_alpn_* and gnutls_ocsp_* functions during
configure instead of relying on the version number.  GnuTLS has options
to turn these features off and we ca just work with with such builds
like we work with older versions.

Signed-off-by: Marcus Hoffmann <m.hoffmann@cartelsol.com>

Closes #1204

Follow-up to 34634080.

Prior to 34634080 file:// hostnames were silently stripped.

Prior to this commit it did not work when a schemeless url was used with
file as the default protocol.

Ref: https://curl.haxx.se/mail/lib-2016-11/0081.html
Closes https://github.com/curl/curl/pull/1124

Also fix for drive letters:

- Support --proto-default file c:/foo/bar.txt

- Support file://c:/foo/bar.txt

- Fail when a file:// drive letter is detected and not MSDOS/Windows.

Bug: https://github.com/curl/curl/issues/1187
Reported-by: Anatol Belski
Assisted-by: Anatol Belski

Regression introduced in commit f682156a

Reported-by: John Kohl
Bug: https://curl.haxx.se/mail/lib-2017-01/0055.html

Both IMAP and POP3 response characters are used internally, but when
appended to the STARTTLS denial message likely could confuse the user.

Closes https://github.com/curl/curl/pull/1203

- Format the numeric denial code as an integer instead of a character.

... when checking for a too large request.

Define _WINSOCKAPI_ blank rather than to 1 in order to match the value
used by Microsoft's winsock header files.

Closes https://github.com/curl/curl/pull/1195

Fixes spurious test 1060 and 1061 failures on OpenBSD, Solaris and more.

Bug: https://curl.haxx.se/mail/lib-2017-01/0009.html
Reported-by: Christian Weisgerber

At least mostly, not counting // comments.

libcurl requires CURLMOPT_SOCKETFUNCTION to KEEP watching socket events
and notify back. Modify event_cb() to continue watching events when
fired.

Fixes #1191
Closes #1192
Fixed-by: Mingliang Zhu

Rename symbol lock to locks to not clash with OW CRTL function name.

Closes #1196

Removed items already fixed, clarified a few others.

Reported in #1190
Reported-by: Dan Jacobson

curl.1 is regenerated

Fixes #1190

Fixes #1184

Since the TCP keep-alive options were added in 705f0f7a the start and
interval default values have been 60, but that wasn't documented.

Bug: https://curl.haxx.se/mail/lib-2017-01/0000.html
Reported-by: Praveen Pvs

This error code was once introduced when some library was dynamically
loaded and a funciton within said library couldn't be found.

Failure to decompress is now a write error instead of the weird
"function not found".