mk-lib1521.pl generates a test program (lib1521.c) that calls
curl_easy_setopt() for every known option with a few typical values to
make sure they work (ignoring the return codes).

Some small changes were necessary to avoid asserts and NULL accesses
when doing this.

The perl script needs to be manually rerun when we add new options.

Closes #1543

These error messages are not displayed with --disable-verbose

This was the only remaining use of toupper in the entire source code.

Suggested-by: Daniel Stenberg

Otherwise, clang on Cygwin64 warns:
curl_ntlm_core.c:525:35: error: array subscript is of type 'char'
[-Werror,-Wchar-subscripts]
    dest[2 * i] = (unsigned char)(toupper(src[i]));
                                  ^~~~~~~~~~~~~~~
/usr/include/ctype.h:152:25: note: expanded from macro 'toupper'
      (void) __CTYPE_PTR[__x]; (toupper) (__x);})
                        ^~~~

Closes https://github.com/curl/curl/pull/1539

Closes #1534

GCC 7 complained:
‘*’ in boolean context, suggest ‘&&’ instead [-Wint-in-bool-context]

This fixes the following warning with CURL_DISABLE_CRYPTO_AUTH,
as seen in the autobuilds:

curl_sasl.c:417:9: warning: unused variable 'serverdata'
[-Wunused-variable]

cyassl/ssl.h needs the macros from cyassl/options.h, so define them
before including cyassl/ssl.h the first time, which happens in
urldata.h.
This broke the build on Ubuntu Xenial, which comes with WolfSSL 3.4.8
and therefore redefines the symbols from cyassl/options.h instead of
including the header.

Closes https://github.com/curl/curl/pull/1536

Closes #1532

Found when updating test 1395, which I did to increase test coverage of
this source file...

Closes #1535

mbedtls_x509_crt_profile_fr is only used locally.
This fixes a missing-variable-declarations warning with clang.

Unaligned access is on purpose here and the warning is harmless on
affected architectures. GCC knows that, while clang warns on all
architectures.

Closes #1529

Closes #1530

... the torture ones are commented out only because they are slooooow.

Closes #1528

... and update the certinfo.c example accordingly.

Fixes https://github.com/curl/curl/issues/846

... so that they get the required "struct curl_tlssessioninfo **"
arguments.

Fixes #1524

Otherwise, they are removed in the final configure file.
Also changed sed to "$SED" like in most other calls in this file.

"clang -dumpversion" always returns "4.2.1", the GCC version that clang
was initially compatible to. Use "clang -v" instead, which returns the
actual clang version.

Fixes https://github.com/curl/curl/issues/1522
Closes https://github.com/curl/curl/pull/1523

... since closesocket is a function in WinSock.

Reported-by: Marcel Raad
Bug: https://github.com/curl/curl/commit/55fcb8485914700132fd1854c9509b66c955efbe#co
mmitcomment-22347818

Use CURLMcode for variable 'res' and cast to int where necessary
instead of the other way around. Other tests do the same.

This fixes the following clang warning:
lib583.c:68:15: warning: cast from function call of type 'CURLMcode' to
non-matching type 'int' [-Wbad-function-cast]

Reported-by: Gisle Vanem