Drop xim-related configure options from the docs

These options have been dropped from configure a while ago,
so they should no longer be in the docs either. Bug 605190.

docs/reference/gtk/building.sgml

@@ -337,14 +337,6 @@ How to compile GTK+ itself
             <arg>--disable-shm</arg>
             <arg>--enable-shm</arg>
           </group>
-          <group>
-            <arg>--disable-xim</arg>
-            <arg>--enable-xim</arg>
-          </group>
-          <group>
-            <arg>--disable-xim-inst</arg>
-            <arg>--enable-xim-inst</arg>
-          </group>
           <group>
             <arg>--disable-xkb</arg>
             <arg>--enable-xkb</arg>
@@ -471,30 +463,6 @@ How to compile GTK+ itself
         </para>
       </formalpara>
 
-      <formalpara>
-        <title><systemitem>--disable-xim</systemitem> and
-          <systemitem>--enable-xim</systemitem></title>
-
-        <para>
-          These options can be used to control whether GTK+ will
-          be compiled with support for XIM. (The X Input Method
-          extension, used for Japanese input.) The default is yes.
-        </para>
-      </formalpara>
-
-      <formalpara>
-        <title><systemitem>--disable-xim-inst</systemitem> and
-          <systemitem>--enable-xim-inst</systemitem></title>
-
-        <para>
-          These options determine whether GTK+ will use the
-          XIM instantiate callback.
-          The default is 'yes', unless the host system is Solaris,
-          where <function>XRegisterIMInstantiateCallback()</function>
-          seems to cause a segfault.
-        </para>
-      </formalpara>
-
       <formalpara>
         <title><systemitem>--disable-xkb</systemitem> and
           <systemitem>--enable-xkb</systemitem></title>