Serve CA full chain (Let's Encrypt), TLS 1.3, fix handshake buffer overflowHEADmain

- tls.c/config.h: read full PEM chain into STACK_OF(X509), send via SSL_set1_chain
- tls.c: minimum protocol TLS 1.2 -> TLS 1.3
- server.c: drain handshake output via local buffer loop instead of staging
  into the fixed 4 KB client buffer (a full CA chain overflowed it -> assert)
- FORK.md: describe the fork

1 files changed, 1 insertions, 0 deletions

diff --git a/include/config.h b/include/config.h
index f893b20..071c253 100644
--- a/include/config.h
+++ b/include/config.h
@@ -38,6 +38,7 @@ struct gmnisrv_host {
 	char *hostname;
 	X509 *x509;
 	EVP_PKEY *pkey;
+	STACK_OF(X509) *chain;
 
 	struct gmnisrv_route *routes;