when using --http2 one can now selectively disable NPN or ALPN with
--no-alpn and --no-npn. for now honored with NSS only.

TODO: honor this option with GnuTLS and OpenSSL

SSL_ENABLE_ALPN can be used for preprocessor ALPN feature detection,
but not SSL_NEXT_PROTO_SELECTED, since it is an enum value and not a
preprocessor macro.

For verify file, if the strippart condition removes the line completely
it is now removed from the array.

It's unnecessary for curl testing, and it can otherwise cause
stunnel to fail to start if OpenSSL doesn't support FIPS mode.

This was already mostly being done, except that analysis after the
test still assumed that the valgrind log files would be available. An
alternative way to handle the valgrind + gdb combination could be to
enable one of the valgrind debugger hooks.

lib1515.c:38:26 warning: unused parameter 'curl'
lib1515.c:38:81 warning: unused parameter 'ptr'
lib1515.c:38:5 warning: no previous prototype for 'debug_callback'
lib1515.c:46:5 warning: no previous prototype for 'do_one_request'
lib1515.c:120:3  warning: ISO C90 forbids mixed declarations and code

As well as some code policing such as white space and braces.

Changed the support to a little matrix and added brief explanation of
what ALPN and NPN are for.

Add ALPN and NPN support for NSS. This allows cURL to negotiate
HTTP/2.0 connections when built with NSS.

Not comma, which is an inconsistency and a mistake probably inherited
from the examples section of RFC1867.

This bug has been present since the day curl started to support
multipart formposts, back in the 90s.

Reported-by: Rob Davies
Bug: http://curl.haxx.se/bug/view.cgi?id=1333

When using the multi socket interface, libcurl calls the
curl_multi_timer_callback asking to be woken up after
CURL_TIMEOUT_EXPECT_100 milliseconds.

After the timeout has expired, calling curl_multi_socket_action with
CURL_SOCKET_TIMEOUT as sockfd leads libcurl to check expired
timeouts. When handling the 100-continue one, the following check in
Curl_readwrite() fails if exactly CURL_TIMEOUT_EXPECT_100 milliseconds
passed since the timeout has been set!

It seems logical to consider that having waited for exactly
CURL_TIMEOUT_EXPECT_100 ms is enough.

Bug: http://curl.haxx.se/bug/view.cgi?id=1334

Offer TLSv1.0 to 1.2 by default, still fall back to SSLv3
if --tlsv1[.N] was not specified on the command line.

Fix for bug #1303 (030a2b8c) was not complete.
libcurl still pruned DNS entries added manually
after detecting a dead connection. This test
checks such behavior.

Test-case 1515 reproduces bug #1303, where libcurl
would incorrectly prune DNS entries added via
CURLOPT_RESOLVE after the DNS_CACHE_TIMEOUT had
expired.

Leave the valgrind --gen-suppressions option in there, commented, to
make it easier for next update.