libinterimap: add support for the TLS SNI (Server Name Indication) extension.

This is controlled by the new 'SSL_hostname' option.  The default value
of that option is the value of the 'host' option when it is hostname,
and the empty string (which disables SNI) when it is an IP literal.

2 files changed, 14 insertions, 0 deletions

diff --git a/doc/interimap.1.md b/doc/interimap.1.md
index d21424b..54c3dcf 100644
--- a/doc/interimap.1.md
+++ b/doc/interimap.1.md
@@ -442,6 +442,13 @@ Valid options are:
 :   File containing trusted certificates to use during server
     certificate verification when `SSL_verify=YES`.
 
+*SSL_hostname*
+
+:   Name to use for the TLS SNI (Server Name Indication) extension.  The
+    default value is taken from the *host* option when it is a hostname,
+    and to the empty string when it is an IP literal.
+    Setting *SSL_hostname* to the empty string explicitly disables SNI.
+
 Supported extensions  {#supported-extensions}
 ====================
 
diff --git a/doc/pullimap.1.md b/doc/pullimap.1.md
index bcf5ade..fb3a73b 100644
--- a/doc/pullimap.1.md
+++ b/doc/pullimap.1.md
@@ -261,6 +261,13 @@ Valid options are:
 :   File containing trusted certificates to use during server
     certificate verification when `SSL_verify=YES`.
 
+*SSL_hostname*
+
+:   Name to use for the TLS SNI (Server Name Indication) extension.  The
+    default value is taken from the *host* option when it is a hostname,
+    and to the empty string when it is an IP literal.
+    Setting *SSL_hostname* to the empty string explicitly disables SNI.
+
 Control flow  {#control-flow}
 ============