Whilst there are no coding standards for the batch files used in curl,
most tend to use lower-case for keywords and upper-case for variables.

Visual Studio project files and updates to makefile.am to follow.

This wasn't possible with the old curlsrc project filenames, but like
commit 2a615a2b and 11397eb6 for libcurl use the built in Visual
Studio macros for the output filenames.

Following commit 957fcd90 and in preparation for adding the VC14
project files renamed the curl source project files.

.. also update formatting and add WinSSL and wolfSSL to the SSL/TLS
handlers list.

This is a new document to consolidate our thread safety information from
several documents (curl-www:features, libcurl.3, libcurl-tutorial.3).
Each document's section on multi-threading will now point to this one.

...as well as some wording.

Closes #355

Closes #322 for now

Closes #349 for now

- Set CURLOPT_SSL_OPTIONS only if the tool enabled an SSL option.

Broken by me several days ago in 172b2beb.
https://github.com/bagder/curl/commit/172b2be#diff-70b44ee478e58d4e1ddcf9c9a73d257b

Bug: http://curl.haxx.se/mail/lib-2015-07/0119.html
Reported-by: Dan Fandrich

To make it easier to link with static versions of OpenSSL, the configure
script now checks if -ldl is needed for linking.

Help-by: TJ Saunders

Currently, libcurl rejects responses with "Content-Encoding: compress"
when CURLOPT_ACCEPT_ENCODING is set to "". I think that libcurl should
treat the Content-Encoding "compress" the same as other
Content-Encodings that it does not support, e.g. "bzip2". That means
just ignoring it.

MSVC 12 complains:

lib\vtls\openssl.c(1554): warning C4701: potentially uninitialized local
variable 'verstr' used It's a false positive, but as it's normally not,
I have enabled warning-as-error for that warning.

This option disables any attempts in configure to create dependency on
stuff requiring linking to librt.so and libpthread.so, in this case this
means clock_gettime(CLOCK_MONOTONIC, &mt).

We were in need to build curl which doesn't link libpthread.so to avoid
the following bug:
https://sourceware.org/bugzilla/show_bug.cgi?id=16628.

Detected by Coverity.

Error: NULL_RETURNS:
lib/http2.c:1301: returned_null: "strchr" returns null (checked 103 out of 109 times).
lib/http2.c:1301: var_assigned: Assigning: "hdbuf" = null return value from "strchr".
lib/http2.c:1302: dereference: Incrementing a pointer which might be null: "hdbuf".
1300|
1301|     hdbuf = strchr(hdbuf, 0x0a);
1302|->   ++hdbuf;
1303|
1304|     authority_idx = 0;

- Fix the VerifyVersionInfo calls, which we use to test for the OS major
version, to also test for the minor version as well as the service pack
major and minor versions.

MSDN: "If you are testing the major version, you must also test the
minor version and the service pack major and minor versions."

https://msdn.microsoft.com/en-us/library/windows/desktop/ms725492.aspx

Bug: https://github.com/bagder/curl/pull/353#issuecomment-123493098


Reported-by: Marcel Raad <MarcelRaad@users.noreply.github.com>

Addition of new procedures curl_pushheader_bynum and curl_pushheader_byname
requires VERSIONINFO updating.

They should not trigger, but in case of internal problems we at least
avoid crashes this way.

New tool option --ssl-no-revoke.
New value CURLSSLOPT_NO_REVOKE for CURLOPT_SSL_OPTIONS.

Currently this option applies only to WinSSL where we have automatic
certificate revocation checking by default. According to the
ssl-compared chart there are other backends that have automatic checking
(NSS, wolfSSL and DarwinSSL) so we could possibly accommodate them at
some later point.

Bug: https://github.com/bagder/curl/issues/264


Reported-by: zenden2k <zenden2k@gmail.com>

.. also fix some typos in test's FILEFORMAT spec.

Static analysis indicated that my commit 9008f3d5 ("ntlm_wb: Fix
hard-coded limit on NTLM auth packet size") introduced a potential
memory leak on an error path, because we forget to free the buffer
before returning an error.

Fix this.

Although actually, it never happens in practice because we never *get*
here with state == NTLMSTATE_TYPE1. The state is always zero. That
might want cleaning up in a separate patch.

Reported-by: Terri Oda

This prevents valgrind from reporting possibly lost memory that NSPR
uses for file descriptor cache and other globally allocated internal
data structures.

Reported-by: Štefan Kremeň

setup-vms.h: More symbols for SHA256, hacks for older VAX

openssl.h: Use OpenSSL OPENSSL_NO_SHA256 macro to allow building on VAX.

openssl.c: Use OpenSSL version checks and OPENSSL_NO_SHA256 macro to
allow building on VAX and 64 bit VMS.