Merge branch '1726-codegen-glib-min-version' into 'master'

gdbus-codegen: Emit GUnixFDLists if an arg has type `h` w/ min-version

Closes #1726

See merge request GNOME/glib!1263

docs/reference/gio/gdbus-codegen.xml

@@ -50,6 +50,7 @@
         <replaceable>VALUE</replaceable>
       </arg>
     </group>
+    <arg><option>--glib-min-version</option> <replaceable>VERSION</replaceable></arg>
     <arg choice="plain">FILE</arg>
     <arg>
       <arg choice="plain" rep="repeat">FILE</arg>
@@ -420,6 +421,30 @@ gdbus-codegen --c-namespace MyApp                           \
       </listitem>
     </varlistentry>
 
+    <varlistentry>
+      <term><option>--glib-min-version</option> <replaceable>VERSION</replaceable></term>
+      <listitem>
+        <para>
+          Specifies the minimum version of GLib which the code generated by
+          <command>gdbus-codegen</command> can depend on. This may be used to
+          make backwards-incompatible changes in the output or behaviour of
+          <command>gdbus-codegen</command> in future, which users may opt in to
+          by increasing the value they pass for <option>--glib-min-version</option>.
+          If this option is not passed, the output from <command>gdbus-codegen</command>
+          is guaranteed to be compatible with all versions of GLib from 2.30
+          upwards, as that is when <command>gdbus-codegen</command> was first
+          released.
+        </para>
+        <para>
+          The version number must be of the form
+          <literal><replaceable>MAJOR</replaceable>.<replaceable>MINOR</replaceable>.<replaceable>MICRO</replaceable></literal>,
+          where all parts are integers. <replaceable>MINOR</replaceable> and
+          <replaceable>MICRO</replaceable> are optional. The version number may not be smaller
+          than <literal>2.30</literal>.
+        </para>
+      </listitem>
+    </varlistentry>
+
   </variablelist>
 </refsect1>