curl_easy_getinfo.3: document 'internals' in CURLINFO_TLS_SESSION

... as it was previouly undocumented what the pointer was.

docs/libcurl/curl_easy_getinfo.3

@@ -5,7 +5,7 @@
 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
-.\" * Copyright (C) 1998 - 2014, Daniel Stenberg, <daniel@haxx.se>, et al.
+.\" * Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
 .\" *
 .\" * This software is licensed as described in the file COPYING, which
 .\" * you should have received as part of this distribution. The terms
@@ -236,6 +236,26 @@ option may not be available for all SSL backends; unsupported SSL backends
 will return 'CURLSSLBACKEND_NONE' to indicate that they are not supported;
 this does not mean that no SSL backend was used. (Added in 7.34.0)
 
+.nf
+struct curl_tlssessioninfo {
+  curl_sslbackend backend;
+  void *internals;
+};
+.fi
+
+The \fIinternals\fP struct member will point to a TLS library specific pointer
+with the following underlying types:
+.RS
+.IP OpenSSL
+SSL_CTX *
+.IP GnuTLS
+gnutls_session_t
+.IP NSS
+PRFileDesc *
+.IP gskit
+gsk_handle
+.RE
+
 .IP CURLINFO_CONDITION_UNMET
 Pass a pointer to a long to receive the number 1 if the condition provided in
 the previous request didn't match (see \fICURLOPT_TIMECONDITION(3)\fP). Alas,