Install dynamically loadable modules into a private subdirectory

under libdir, for a cleaner separation in the installation layout
and compatibility with binary packaging standards.  Point backend's
default search location there.  The contrib modules are also
installed in the said location, giving them the benefit of the
default search path as well.  No changes in user interface
nevertheless.

doc/src/sgml/installation.sgml

@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.55 2001/09/12 20:57:28 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/installation.sgml,v 1.56 2001/09/16 16:11:09 petere Exp $ -->
 
 <chapter id="installation">
  <title><![%flattext-install-include[<productname>PostgreSQL</>]]>
@@ -471,9 +471,11 @@ su - postgres
        <varname>includedir</varname> and are namespace-clean.  The
        internal header files and the server header files are installed
        into private directories under
-       <filename><replaceable>includedir</replaceable>/postgresql</filename>.
+       <varname>includedir</varname>.
        See the <citetitle>Programmer's Guide</citetitle> for
        information how to get at the header files for each interface.
+       Finally, a private subdirectory will also be created, if appropriate,
+       under <varname>libdir</varname> for dynamically loadable modules.       
       </para>
      </note>
     </para>

doc/src/sgml/ref/pg_config-ref.sgml

@@ -1,4 +1,4 @@
-<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/pg_config-ref.sgml,v 1.7 2001/09/03 12:57:50 petere Exp $ -->
+<!-- $Header: /cvsroot/pgsql/doc/src/sgml/ref/pg_config-ref.sgml,v 1.8 2001/09/16 16:11:09 petere Exp $ -->
 
 <refentry id="app-pgconfig">
  <docinfo>
@@ -24,6 +24,7 @@
     <arg>--includedir</arg>
     <arg>--includedir-server</arg>
     <arg>--libdir</arg>
+    <arg>--pkglibdir</arg>
     <arg>--configure</arg>
     <arg>--version</arg>
    </group>
@@ -87,6 +88,18 @@
      </listitem>
     </varlistentry>
 
+    <varlistentry>
+     <term>--pkglibdir</>
+     <listitem>
+      <para>
+       Print the location of dynamically loadable modules, or where
+       the server would search for them.  (Other
+       architecture-dependent data files may also be installed in this
+       directory.)
+      </para>
+     </listitem>
+    </varlistentry>
+
     <varlistentry>
      <term>--configure</>
      <listitem>

doc/src/sgml/runtime.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.79 2001/09/13 15:55:23 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/runtime.sgml,v 1.80 2001/09/16 16:11:09 petere Exp $
 -->
 
 <Chapter Id="runtime">
@@ -1047,12 +1047,13 @@ env PGOPTIONS='-c geqo=off' psql
         The value for dynamic_library_path has to be a colon-separated
         list of absolute directory names.  If a directory name starts
         with the special value <literal>$libdir</literal>, the
-        compiled-in PostgreSQL library directory, which is where the
+        compiled-in PostgreSQL package library directory, which is where the
         modules provided by the PostgreSQL distribution are installed,
-        is substituted.  An example value:
+        is substituted.  (Use <literal>pg_config --pkglibdir</literal>
+        to print the name of this directory.)  An example value:
         <informalexample>
 <programlisting>
-dynamic_library_path = '/usr/local/lib:/home/my_project/lib:$libdir:$libdir/contrib'
+dynamic_library_path = '/usr/local/lib/postgresql:/home/my_project/lib:$libdir'
 </programlisting>
         </informalexample>
        </para>

doc/src/sgml/xfunc.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.37 2001/09/15 19:56:59 petere Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xfunc.sgml,v 1.38 2001/09/16 16:11:09 petere Exp $
 -->
 
  <chapter id="xfunc">
@@ -466,7 +466,7 @@ CREATE FUNCTION square_root(double precision) RETURNS double precision
      <listitem>
       <para>
        If the name starts with the string <literal>$libdir</literal>,
-       that part is replaced by the PostgreSQL library directory,
+       that part is replaced by the PostgreSQL package library directory,
        which is determined at build time.
       </para>
      </listitem>
@@ -516,7 +516,9 @@ CREATE FUNCTION square_root(double precision) RETURNS double precision
     It is recommended to locate shared libraries either relative to
     <literal>$libdir</literal> or through the dynamic library path.
     This simplifies version upgrades if the new installation is at a
-    different location.
+    different location.  The actual directory that
+    <literal>$libdir</literal> stands for can be found out with the
+    command <literal>pg_config --pkglibdir</literal>.
    </para>
 
    <note>