windows.cfg: Added support for PurgeCom(). Reference: https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-purgecomm

cfg/windows.cfg

@@ -1752,6 +1752,17 @@
       <not-uninit/>
     </arg>
   </function>
+  <!-- BOOL PurgeComm(HANDLE hFile, DWORD  dwFlags);-->
+  <function name="PurgeComm">
+    <noreturn>false</noreturn>
+    <returnValue type="BOOL"/>
+    <arg nr="1" direction="in">
+      <not-uninit/>
+    </arg>
+    <arg nr="2" direction="in">
+      <not-uninit/>
+    </arg>
+  </function>
   <!-- BOOL WINAPI SetCommState(
   _In_  HANDLE hFile,
   _In_  LPDCB lpDCB);-->