alternative failures markup syntax (per http://article.gmane.org/gmane.comp.lib.boost.devel/108605)

[SVN r25204]

status/explicit-failures.xsd

@@ -27,6 +27,7 @@
             <xs:sequence>
                 <xs:element ref="mark-unusable" minOccurs="0" maxOccurs="unbounded"/>
                 <xs:element ref="test" minOccurs="0" maxOccurs="unbounded"/>
+                <xs:element ref="mark-expected-failures" minOccurs="0" maxOccurs="unbounded"/>
             </xs:sequence>
             <xs:attribute name="name" type="xs:string" use="required"/>
         </xs:complexType>
@@ -53,6 +54,16 @@
         </xs:complexType>
     </xs:element>
 
+    <xs:element name="mark-expected-failures">
+        <xs:complexType>
+            <xs:sequence>
+                <xs:element ref="test" minOccurs="0" maxOccurs="unbounded"/>
+                <xs:element ref="toolset" minOccurs="0"/>
+                <xs:element ref="note" minOccurs="0"/>
+            </xs:sequence>
+        </xs:complexType>
+    </xs:element>
+
     <xs:element name="mark-failure">
         <xs:complexType>
             <xs:sequence>