This extends the target selection implemented in dad6ec3aa63f to support
Windows ARM64 platforms.  OpenSSL support for VC-WIN64-ARM target first
appeared in 1.1.1 and is present in all currently supported (3.x)
branches.

As a side effect, ARM64 Windows builds will get 16-byte alignment along
with the rest of non-x86 platforms.  This is safe, as malloc on 64-bit
Windows guarantees the fundamental alignment of allocations, 16 bytes.

Signed-off-by: Piotr Sikora <piotr@aviatrix.com>

With this change, the NGX_OPENSSL_NO_CONFIG macro is defined when nginx
is asked to build OpenSSL itself.  And with this macro automatic loading
of OpenSSL configuration (from the build directory) is prevented unless
the OPENSSL_CONF environment variable is explicitly set.

Note that not loading configuration is broken in OpenSSL 1.1.1 and 1.1.1a
(fixed in OpenSSL 1.1.1b, see https://github.com/openssl/openssl/issues/7350).
If nginx is used to compile these OpenSSL versions, configuring nginx with
NGX_OPENSSL_NO_CONFIG explicitly set to 0 might be used as a workaround.

To ensure proper target selection the NGX_MACHINE variable is now set
based on the MSVC compiler output, and the OpenSSL target is set based
on it.

This is not important as long as "no-asm" is used (as in misc/GNUmakefile
and win32 build instructions), but might be beneficial if someone is trying
to build OpenSSL with assembler code.

The change allows to compile QUIC with OpenSSL which lacks BoringSSL QUIC API.

This implementation does not support 0-RTT.

Threads are disabled during UNIX builds (see b329c0ab1a48), and also not
needed for Windows builds.

This used to be the default before OpenSSL 1.1.0.

OpenSSL library QUIC support cannot be tested at configure time when
using the --with-openssl option so assume it's present if requested.
While here, fixed the error message in case QUIC support is missing.