This reduces the number of moving parts in ABI compatibility checks.
Additionally, it also allows to use OpenSSL in FIPS mode while still
using md5 for non-security tasks.

OPENSSL_config() deprecated in OpenSSL 1.1.0.  Additionally,
SSL_library_init(), SSL_load_error_strings() and OpenSSL_add_all_algorithms()
are no longer available if OPENSSL_API_COMPAT is set to 0x10100000L.

The OPENSSL_init_ssl() function is now used instead with appropriate
arguments to trigger the same behaviour.  The configure test changed to
use SSL_CTX_set_options().

Deinitialization now happens automatically in OPENSSL_cleanup() called
via atexit(3), so we no longer call EVP_cleanup() and ENGINE_cleanup()
directly.

The install_sw target first appeared in OpenSSL 0.9.7e and is documented since
OpenSSL 1.0.0 as the way to install the OpenSSL software without documentation.

Before 7142b04337d6, it was possible to build the OpenSSL library
along with nginx, and link nginx statically with this library
(--with-openssl=DIR --with-ld-opt=-static --with-http_ssl_module).
This was broken on Linux by not adding -ldl after -lcrypto.

The fix also makes it possible to link nginx statically on Linux
with the system OpenSSL library, which never worked before.

Now we always set NGX_CC_NAME to "msvc", and additionally test compiler
version as reported by "cl" in auto/cc/msvc (the same version is also
available via the _MSC_VER define).  In particular, this approach allows
to properly check for C99 variadic macros support, which previously was
not used with MSVC versions not explicitly recognized.

Now unneeded wildcards in NGX_CC_NAME tests for msvc removed accordingly,
as well as unused wildcards for owc and icc.

The auto/module script is extended to understand ngx_module_link=DYNAMIC.
When set, it links the module as a shared object rather than statically
into nginx binary.  The module can later be loaded using the "load_module"
directive.

New auto/module parameter ngx_module_order allows to define module loading
order in complex cases.  By default the order is set based on ngx_module_type.

3rd party modules can be compiled dynamically using the --add-dynamic-module
configure option, which will preset ngx_module_link to "DYNAMIC" before
calling the module config script.

Win32 support is rudimentary, and only works when using MinGW gcc (which
is able to handle exports/imports automatically).

In collaboration with Ruslan Ermilov.

The workaround from baf2816d556d stopped to work because the order of
"-arch x86_64" and "-arch i386" has changed.