Document unavailable parameters in some configurations

Add a note to user-facing parameters that can be removed completely
(and not just empty) by #ifdef's depending on build configuration.

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 3284c70e22f546f3ae58cef670e79b2ba66163ce..1b8e5a5259a5c73d1b92de47137d1477825eedf0 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -687,7 +687,8 @@ SET ENABLE_SEQSCAN TO OFF;
        
         Specifies a list of SSL ciphers that are allowed to be
         used on secure connections. See the openssl
-        manual page for a list of supported ciphers.
+        manual page for a list of supported ciphers. This parameter is
+        unavailable unless the server is compiled with support for SSL.
        
       
      
@@ -2969,7 +2970,8 @@ local0.*    /var/log/postgresql
         documentation of your system's
         syslog daemon.
         This parameter can only be set in the postgresql.conf
-        file or on the server command line.
+        file or on the server command line. This parameter is unavailable
+        unless the server is compiled with support for syslog.
        
       
      
@@ -2987,7 +2989,8 @@ local0.*    /var/log/postgresql
          syslog logs. The default is
          postgres.
          This parameter can only be set in the postgresql.conf
-         file or on the server command line.
+         file or on the server command line. This parameter is unavailable
+         unless the server is compiled with support for syslog.