Update explicit-failures-markup.xml

[skip ci]

status/explicit-failures-markup.xml

@@ -2865,6 +2865,23 @@
         </mark-expected-failures>
     </library>
 
+    <!-- json -->
+    <library name="json">
+        <mark-unusable>
+            <toolset name="*c++98"/>
+            <toolset name="*gnu98"/>
+            <toolset name="*c++0x"/>
+            <toolset name="*gnu0x"/>
+            <toolset name="msvc-7.1"/>
+            <toolset name="msvc-8.*"/>
+            <toolset name="msvc-9.*"/>
+            <toolset name="msvc-10.*"/>
+            <toolset name="msvc-11.*"/>
+            <toolset name="msvc-12.*"/>
+            <note author="Vinnie Falco">C++11 is the minimum requirement.</note>
+        </mark-unusable>
+    </library>
+
     <!-- lambda -->
     <library name="lambda">
         <mark-unusable>