clang 2.9+ supports -Wshift-sign-overflow, which warns about undefined
behavior on signed left shifts when shifting by too many places.

Ref: https://github.com/curl/curl/issues/1516
Closes https://github.com/curl/curl/pull/1517

wolfSSL configure script relevant changes from 3.10 to 3.11:

- Async threading support added; disabled by default without async
  crypto, which continues to be disabled by default.

wolfSSL configure script relevant changes from 3.11 to 3.11.1 (beta):

- TLS 1.3 beta support added; disabled by default.

For experimenting I put in a comment block the defines needed to enable
TLS 1.3 support (ie the equivalent of --enable-tls13).

Fixes #1208

... with a strlen() if no size was set, and do this in the pretransfer
function so that the info is set early. Otherwise, the default strlen()
done on the POSTFIELDS data never sets state.infilesize.

Reported-by: Vincas Razma
Bug: #1294

- Test curl_msnprintf negative int width arg using INT_MIN instead of
  1 << 31 which is undefined behavior.

Closes https://github.com/curl/curl/issues/1516

vtls/mbedtls.c:804:69: warning: declaration of 'entropy' shadows a global declaration [-Wshadow]
 CURLcode Curl_mbedtls_random(struct Curl_easy *data, unsigned char *entropy,
                                                                     ^~~~~~~

This hasn't been used in over a decade. <precheck> can still be used to
run commands before the main test.

Closes #1509

follow-up to f31760e6

Reported-by: Michael Kaufmann
Bug: https://github.com/curl/curl/pull/1495#issuecomment-303982793

Fix bugs and compiler warnings on systems with 32-bit long and
64-bit time_t.

Reviewed-by: Daniel Stenberg

Closes #1499

This is contained in -Wextra with GCC 7.

Closes #1321

Test 1261 added to verify.

Reported-by: Lloyd Fournier

Fixes #1489
Closes #1497

* LDAP: using ldap_bind_s on Windows with methods(BASIC/DIGEST/NTLM/AUTONEG)

* ldap: updated per build options handling

* ldap: fixed logic for auth selection

Fixed a syntax error with setting cache variables (The type and
docstring were missing), resulting in build errors.  Quoted the
CURL_CA_PATH and CURL_CA_BUNDLE otherwise the path was written without
quotes in C code, resulting in build errors.

Closes #1503

Signed-off-by: Akhil <akhil.kedia@samsung.com>

follow-up to 4cdb1be8

.... caused by a typo in the last commit (fixing issue #1504):

memdebug.c: In function ‘curl_fclose’:
memdebug.c:444:3: error: implicit declaration of function
‘DEBUGDEBUGASSERT’ [-Werror=implicit-function-declaration]

... as it does extra checks to actually work.

Reported-by: jonrumsey at github
Fixes #1504

Closes #1461

This is for symmetry with the autoconf generated curl_config.h.in

Pass the invalid domain name on stdin. On some systems, the test
framework cannot pass invalid UTF-8 sequences on the command line.

Closes #1488

... as otherwise it risks not cleaning up the libssh2 handle properly
which leads to memory leak!

Assisted-by: Joel Depooter

Closes #1495
Closes #1479

Bug: https://curl.haxx.se/mail/lib-2017-04/0024.html

It takes someone to read up on the APIs of these libraries to figure out
how to do this correctly.

Reported-by: Michael Kaufmann

Closes #1253

That means delete the timer.

Reported-by: Michael Kaufmann
Ref: #1253