Otherwise it expands to:

    echo ""/etc/pki/tls/certs/ca-bundle.crt""

Detected by ShellCheck:

    curl-config:74:16: warning: The double quotes around this do
    nothing.  Remove or escape them. [SC2140]

In that case, we only skip writing the error message for failed NSS
initialization (while still returning the correct error code).

The vtls layer now checks the return value, so it is no longer necessary
to abort if a random number cannot be provided by NSS.  This also fixes
the following Coverity report:

Error: FORWARD_NULL (CWE-476):
lib/vtls/nss.c:1918: var_compare_op: Comparing "data" to null implies that "data" might be null.
lib/vtls/nss.c:1923: var_deref_model: Passing null pointer "data" to "Curl_failf", which dereferences it.
lib/sendf.c:154:3: deref_parm: Directly dereferencing parameter "data".

... and remove some old ones

This reverts commit 03fa5768.

obj_count can be 1 if the custom read function is set or the stdin
handle is a reference to a pipe. Since the pipe should be handled
using the PeekNamedPipe-check below, the custom read function should
only be used if it is actually enabled.

According to [1]: "Returning 0 will signal end-of-file to the library
and cause it to stop the current transfer."
This change makes the Windows telnet code handle this case accordingly.

 [1] http://curl.haxx.se/libcurl/c/CURLOPT_READFUNCTION.html

... by making sure the first request is completed before doing the
remainder.

... even if the last IPv6 connection attempt has failed.

Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1187531#c4

... in case the protocol versions are mixed in a DNS response
(IPv6 -> IPv4 -> IPv6).

Bug: https://bugzilla.redhat.com/show_bug.cgi?id=1187531#c3

Remove cmake as marked for removal. It is in much better state now.

SSL_CTX_load_verify_locations by default (and if given non-Null
parameters) searches the CAfile first and falls back to CApath.  This
allows for CAfile to be a basis (e.g. installed by the package manager)
and CApath to be a user configured directory.

This wasn't reflected by the previous configure constraint which this
patch fixes.

Bug: https://github.com/bagder/curl/pull/139

Correctly check for memcmp() return value (it returns 0 if the strings match).

This is not really important, since curl is going to use http/1.1 anyway, but
it's still a bug I guess.

Correctly check for strncmp() return value (it returns 0 if the strings
match).

Use "cmake -E echo" instead of "echo".

Reviewed-by: Brad King <brad.king@kitware.com>

Set CMAKE_REQUIRED_DEFINITIONS to include definitions needed to get
the winsock2 API from windows.h.  Simplify the order of checks to
avoid extra conditions.

Use check_include_file instead of check_include_file_concat to look
for OpenSSL headers.  They do not need to participate in a sequence
of dependent system headers.  Also they may cause winsock.h to be
included before ws2tcpip.h, causing the latter to not be detected
in the sequence.

Reviewed-by: Brad King <brad.king@kitware.com>

Visual Studio 2005 and above defaults to disabling the startup banner
for the Compiler, Linker and MIDL tools (with /NOLOGO). As such there
is no need to explicitly set the SuppressStartupBanner directive, as
this is a leftover from the VC7 and VC7.1 projects being upgraded to
VC8 and above.

lib/vtls/openssl.c:1450:7: warning: extra tokens at end of #endif directive

For consistency with other conditionally compiled code in openssl.c,
use OPENSSL_IS_BORINGSSL rather than HAVE_BORINGSSL and try to use
HAVE_BORINGSSL outside of openssl.c when the OpenSSL header files are
not included.

Versions of OpenSSL prior to v0.9.8h do not support the necessary
functions for OCSP stapling.

Previously we don't ignore PUSH_PROMISE header fields in on_header
callback.  It makes header values mixed with following HEADERS,
resulting protocol error.

Prior to this change the options for exclusive SSL protocol versions did
not actually set the protocol exclusive.

http://curl.haxx.se/mail/lib-2015-01/0002.html
Reported-by: Dan Fandrich

Reported-by: Jon Seymour