windows.cfg: Added support for _swap().

cfg/windows.cfg

@@ -3086,4 +3086,23 @@ HFONT CreateFont(
       <not-uninit/>
     </arg>
   </function>
+  <!-- void _swab(char *src, char *dest, int n);-->
+  <function name="_swab">
+    <noreturn>false</noreturn>
+    <leak-ignore/>
+    <arg nr="1">
+      <not-null/>
+      <minsize type="argvalue" arg="3"/>
+    </arg>
+    <arg nr="2">
+      <not-null/>
+      <not-uninit/>
+      <minsize type="argvalue" arg="3"/>
+    </arg>
+    <arg nr="3">
+      <not-uninit/>
+      <not-bool/>
+      <valid>0:</valid>
+    </arg>
+  </function>
 </def>