I run a centos 7.6 server with nginx. Centos repos do not have latest nginx, so I compiled manually using instructions from here.
This left me a nginx binary:
nginx version: nginx/1.15.8
built by gcc 7.2.0
built with OpenSSL 1.1.1a 20 Nov 2018
TLS SNI support enabled
configure arguments: --sbin-path=/usr/local/sbin --conf-path=/etc/nginx/nginx.conf --pid-path=/var/run/nginx.pid --http-log-path=/var/log/nginx/access.log --error-log-path=/var/log/nginx/error.log --http-client-body-temp-path=/var/cache/nginx/client_temp --http-proxy-temp-path=/var/cache/nginx/proxy_temp --http-fastcgi-temp-path=/var/cache/nginx/fastcgi_temp --http-uwsgi-temp-path=/var/cache/nginx/uwsgi_temp --http-scgi-temp-path=/var/cache/nginx/scgi_temp --with-pcre=/n/pcre-8.42 --with-openssl=/n/openssl-1.1.1a --with-zlib=/n/zlib-1.2.11 --with-file-aio --with-http_ssl_module --with-http_v2_module --with-stream --with-stream_ssl_module --with-threads
which worked with TLS 1.3.
However I installed gcc 8.2 as well from https://cbs.centos.org/. It installed correctly, and I tried to rebuild nginx with the new compiler. Still the same output, still the same binary, but no TLS 1.3. Chrome says it is a TLS 1.2 connection, SSLlabs says no tls 1.3 support.
I tried recompiling with gcc 7.2.0, still same result.
What could be wrong?
Thanks.