Add a note about the profiling versions of the interface files in a package.
<listitem>
<para>A list of directories containing interface files
(<literal>.hi</literal> files) for this package.</para>
<listitem>
<para>A list of directories containing interface files
(<literal>.hi</literal> files) for this package.</para>
+
+ <para>If the package contains profiling libraries, then
+ the interface files for those library modules should have
+ the suffix <literal>.p_hi</literal>. So the package can
+ contain both normal and profiling versions of the same
+ library without conflict (see also
+ <literal>library_dirs</literal> below).</para>
</listitem>
</varlistentry>
</listitem>
</varlistentry>