comctl32: Constify some variables (5 of 12)

[Andrew Talbot]

Changelog:
    comctl32: Constify some variables.

diff -urN a/dlls/comctl32/header.c b/dlls/comctl32/header.c
--- a/dlls/comctl32/header.c	2007-03-27 17:43:39.000000000 +0100
+++ b/dlls/comctl32/header.c	2007-03-31 15:00:44.000000000 +0100
@@ -740,8 +740,8 @@
  * 
  * NOTE: We depend on HDITEMA and HDITEMW having the same structure
  */
-static void HEADER_CopyHDItemForNotify(HEADER_INFO *infoPtr, HDITEMW *dest,
-    HDITEMW *src, BOOL fSourceUnicode, LPVOID *ppvScratch)
+static void HEADER_CopyHDItemForNotify(const HEADER_INFO *infoPtr, HDITEMW *dest,
+    const HDITEMW *src, BOOL fSourceUnicode, LPVOID *ppvScratch)
 {
     *ppvScratch = NULL;
     *dest = *src;
@@ -1394,7 +1394,7 @@
 }
 
 static LRESULT
-HEADER_SetItemT (HWND hwnd, INT nItem, LPHDITEMW phdi, BOOL bUnicode)
+HEADER_SetItemT (HWND hwnd, INT nItem, const HDITEMW *phdi, BOOL bUnicode)
 {
     HEADER_INFO *infoPtr = HEADER_GetInfoPtr (hwnd);
     HEADER_ITEM *lpItem;