[gtk-doc] docs: share a trick about gtk-doc dependecy

[Stefan Kost <stefkost src gnome org>]

commit f57c90e125679a2bcadf739ca894e68c9f7af3f4
Author: Stefan Kost <ensonic users sf net>
Date:   Mon Sep 13 14:52:52 2010 +0300

    docs: share a trick about gtk-doc dependecy

 help/manual/C/gtk-doc-manual.xml |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)
---
diff --git a/help/manual/C/gtk-doc-manual.xml b/help/manual/C/gtk-doc-manual.xml
index bb3329b..58c3122 100644
--- a/help/manual/C/gtk-doc-manual.xml
+++ b/help/manual/C/gtk-doc-manual.xml
@@ -418,6 +418,23 @@ GTK_DOC_CHECK([1.14],[--flavour no-tmpl])
       </para>
       
       <para>
+        This will require all developers to have gtk-doc installed. If it is
+        okay for your project to have optional api-doc build setup, you can
+        solve this as below. Keep it as is, as gtkdocize is looking for
+        <function>GTK_DOC_CHECK</function>  at the start of a line.
+        <example><title>Keep gtk-doc optional</title>
+          <programlisting>
+<![CDATA[
+# check for gtk-doc
+m4_ifdef([GTK_DOC_CHECK], [
+GTK_DOC_CHECK([1.14],[--flavour no-tmpl])
+])
+]]>
+          </programlisting>
+        </example>
+      </para>
+      
+      <para>
         The first argument is used to check for the gtkdocversion at configure time.
         The 2nd, optional argument is used by <application>gtkdocize</application>.
         The <symbol>GTK_DOC_CHECK</symbol> macro also adds several configure switches: