explorerframe: Constify some variables.

dlls/explorerframe/explorerframe_main.c

@@ -211,7 +211,7 @@ HRESULT WINAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, void **ppv)
 /*************************************************************************
  *          Register/Unregister DLL, based on shdocvw/factory.c
  */
-static HRESULT reg_install(LPCSTR section, STRTABLEA *strtable)
+static HRESULT reg_install(LPCSTR section, const STRTABLEA *strtable)
 {
     HRESULT (WINAPI *pRegInstall)(HMODULE hm, LPCSTR pszSection, const STRTABLEA* pstTable);
     HMODULE hadvpack;

dlls/explorerframe/nstc.c

@@ -422,7 +422,7 @@ static void collapse_all(NSTC2Impl *This, HTREEITEM node)
     if(next) collapse_all(This, next);
 }
 
-static HTREEITEM treeitem_from_point(NSTC2Impl *This, POINT *pt, UINT *hitflag)
+static HTREEITEM treeitem_from_point(NSTC2Impl *This, const POINT *pt, UINT *hitflag)
 {
     TVHITTESTINFO tviht;
     tviht.pt.x = pt->x;