After squashing most of our compiler warnings, up'ed the default
warning level from 3 to 4 in order to increase the likelyhood of
catching future warnings.

may be null in the CURLOPT_CONNECT_ONLY case

Fixes #747

From commit 7218b52c.

Corrected typos from commit ad5e9bfd and 6d6f9ca1.

Follow up to commit 7db9782d.

When an upload is done, there are two places where that can be detected
and only one of them would rewind the input stream - which sometimes is
necessary for example when doing NTLM HTTP POSTs and more.

This could then end up libcurl hanging.

Figured-out-by: Isaac Boukris
Reported-by: Anatol Belski

Fixes #741

So that we only do the extra typedefs in curl_memory.h when we really
need to and avoid double typedefs.

follow-up commit to 7218b52c

Thanks-to: Steve Holme

The define is not in our name space and is therefore not protected by
our API promises.

It was only really used by libcurl internals but was mostly erased from
there already in 8aabbf5f (March 2015). This is supposedly the final
death blow to that define from everywhere.

As a side-effect, making sure _MPRINTF_REPLACE is gone and not used, I
made the lib tests in tests/libtest/ use curl_printf.h for its redefine
magic and then subsequently the use of sprintf() got banned in the tests
as well (as it is in libcurl internals) and I then replaced them all
with snprintf().

In the unlikely event that any users is actually using this define and
gets sad by this change, it is very easily copied to the user's own
code.

Discussed in #743

Fixed copy/paste error from commit a5aec587.

Bug: https://github.com/curl/curl/issues/744
Reported-by: Alexis La Goutte

Supports HTTP/2 over clear TCP

- Optimize switching to HTTP/2 by removing calls to init and setup
before switching. Switching will eventually call setup and setup calls
init.

- Supports new version to “force” the use of HTTP/2 over clean TCP

- Add common line parameter “--http2-prior-knowledge” to the Curl
  command line tool.

The list and search response functions were identical! Merged into one
now. Detected by PVS Studio.

Reported-by: Alexis La Goutte

The code copied one byte from a 32bit integer, which works fine as long
as the byte order is the same. Not a fine assumption. Reported by PVS
Studio.

Reported-by: Alexis La Goutte

... as we check for a NULL pointer below, we move the derefence to after
the check. Detected by PVS Studio.

Reported-by: Alexis La Goutte

... as it doesn't change in between. Deteced by PVS Studio.

Reported-by: Alexis La Goutte

When compiling with OpenSSL 1.1.0 (so that the HAVE_X509_GET0_SIGNATURE
&& HAVE_X509_GET0_EXTENSIONS pre-processor block is active), Visual C++
14 complains:

warning C4701: potentially uninitialized local variable 'palg' used
warning C4701: potentially uninitialized local variable 'psig' used

... as it now is used by multi.c only.

now a file local function in multi.c

... called multi_do and multi_do_done as they're file local now.

https://github.com/wolfSSL/wolfssl/issues/366

This is an update to the build-time options used to build wolfSSL in
Visual Studio for greater compatibility, and make it behave similar to
the way OpenSSL 1.0.2 behaves. Starting in wolfSSL v3.6.6 static ciphers
and SSLv3 are disabled by default at build time, but we can use both.

- Enable static cipher suites TLS_ECDH_ and TLS_RSA_.

- Enable SSLv3 hello. Though in libcurl we disable it by default at
runtime, we make it available so the user can manually select it if
necessary.

Also display the GSS_C_GSS_CODE (major code) when specified instead of
only GSS_C_MECH_CODE (minor code).

In addition, the old code was printing a colon twice after the prefix
and also miscalculated the length of the buffer in between calls to
gss_display_status (the length of ": " was missing).

Also, gss_buffer is not guaranteed to be NULL terminated and thus need
to restrict reading by its length.

Closes #738

... load file specified as argument.

Since commit a5aec587 the handler schemes need to match for the
connections to be reused and for HTTP/2 multiplexing to work, reusing
connections is very important!

Closes #736

Closes #733

This is a follow up to the previous commit.

Closes #492

Skipping the scripts dir is primarily done for 'make install' so that it
does not attempt to install the zsh completion script as we've not yet
found a proper way to do/run that at install time.

By leaving the script dir's Makefile in place, a user can still opt to
run make install manually in there.

Closes #620

... to make them appear as links on the html version.