Protect ILIsParent from NULL pidls

[Dmitry Timoshkov]

Hello,

IE calls ILIsParent with NULL pidlParent.

Changelog:
    Dmitry Timoshkov <dmitry at codeweavers.com>
    Protect ILIsParent from NULL pidls.

--- cvs/hq/wine/dlls/shell32/pidl.c	Fri Oct 10 22:05:33 2003
+++ wine/dlls/shell32/pidl.c	Mon Nov  3 20:20:49 2003
@@ -543,6 +543,8 @@ BOOL WINAPI ILIsParent(LPCITEMIDLIST pid
 
 	TRACE("%p %p %x\n", pidlParent, pidlChild, bImmediate);
 
+	if (!pParent || !pChild) return FALSE;
+
 	while (pParent->mkid.cb && pChild->mkid.cb)
 	{
 	  _ILSimpleGetText(pParent, szData1, MAX_PATH);