SSL: SSL_sendfile() support with kernel TLS. Requires OpenSSL 3.0 compiled with "enable-ktls" option. Further, KTLS needs to be enabled in kernel, and in OpenSSL, either via OpenSSL configuration file or with "ssl_conf_command Options KTLS;" in nginx configuration. On FreeBSD, kernel TLS is available starting with FreeBSD 13.0, and can be enabled with "sysctl kern.ipc.tls.enable=1" and "kldload ktls_ocf" to load a software backend, see man ktls(4) for details. On Linux, kernel TLS is available starting with kernel 4.13 (at least 5.2 is recommended), and needs kernel compiled with CONFIG_TLS=y (with CONFIG_TLS=m, which is used at least on Ubuntu 21.04 by default, the tls module needs to be loaded with "modprobe tls").

# Copyright (C) Igor Sysoev
# Copyright (C) Nginx, Inc.


if [ $PCRE != NONE -a $PCRE != NO -a $PCRE != YES ]; then
    . auto/lib/pcre/make
fi

if [ $OPENSSL != NONE -a $OPENSSL != NO -a $OPENSSL != YES ]; then
    . auto/lib/openssl/make
fi

if [ $ZLIB != NONE -a $ZLIB != NO -a $ZLIB != YES ]; then
    . auto/lib/zlib/make
fi

if [ $NGX_LIBATOMIC != NO -a $NGX_LIBATOMIC != YES ]; then
    . auto/lib/libatomic/make
fi

if [ $USE_PERL != NO ]; then
    . auto/lib/perl/make
fi