Similarly to the QUIC API originated in BoringSSL, this API allows
to register custom TLS callbacks for an external QUIC implementation.
See the SSL_set_quic_tls_cbs manual page for details.

Due to a different approach used in OpenSSL 3.5, handling of CRYPTO
frames was streamlined to always write an incoming CRYPTO buffer to
the crypto context.  Using SSL_provide_quic_data(), this results in
transient allocation of chain links and buffers for CRYPTO frames
received in order.  Testing didn't reveal performance degradation of
QUIC handshakes, https://github.com/nginx/nginx/pull/646 provides
specific results.

All definitions now set in ngx_event_quic.h, this includes moving
NGX_QUIC_OPENSSL_COMPAT from autotests to compile time.  Further,
to improve code readability, a new NGX_QUIC_QUICTLS_API macro is
used for QuicTLS that provides old BoringSSL QUIC API.

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.

The build location of the resulting libatomic_ops.a was changed in v7.4.0
after converting libatomic_ops to use libtool.  The fix is to use library
from the install path, this allows building with both old and new versions.

Initially reported here:
https://mailman.nginx.org/pipermail/nginx/2018-April/056054.html

Using "long *" instead of "AO_t *" leads either to -Wincompatible-pointer-types
or -Wpointer-sign warnings, depending on whether long and size_t are compatible
types (e.g., ILP32 versus LP64 data models).  Notably, -Wpointer-sign warnings
are enabled by default in Clang only, and -Wincompatible-pointer-types is an
error starting from GCC 14.

Signed-off-by: Edgar Bonet <bonet@grenoble.cnrs.fr>

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.