SunPro 5.3 is unusable with Signals, Tuple

[SVN r28321]

status/explicit-failures-markup.xml

@@ -1696,6 +1696,9 @@ for more information.
 
     <!-- signals -->
     <library name="signals">
+        <mark-unusable>
+            <toolset name="sunpro-5_3"/>
+        </mark-unusable>
         <test name="dead_slot_test">
             <mark-failure>
                 <toolset name="*como-4_3_3*"/>
@@ -1833,6 +1836,9 @@ for more information.
 
     <!-- tuple -->
     <library name="tuple">
+        <mark-unusable>
+            <toolset name="sunpro-5_3"/>
+        </mark-unusable>
         <test name="io_test">
             <toolset name="intel-win32"/>
             <note author="B. Dawes" refid="3"/>