Replaced calls to KERNEL.Yield16 by calls to KERNEL32.K32WOWYield from
outside libkernel.so.

diff --git a/windows/winhelp.c b/windows/winhelp.c
index 012d4fd..ff690f8 100644
--- a/windows/winhelp.c
+++ b/windows/winhelp.c
@@ -44,7 +44,7 @@
       /* try to start the 16-bit winhelp */
       if (WinExec( "winhelp.exe -x", SW_SHOWNORMAL ) >= 32)
       {
-          Yield16();
+          K32WOWYield16();
           ret = WinHelpA( hWnd, lpHelpFile, wCommand, (DWORD)MapSL(dwData) );
       }
   }