Moved some more 16-bit functions to user16.c.
A few fixes for -DSTRICT.

diff --git a/windows/winhelp.c b/windows/winhelp.c
index b9bfd85..6f5e3c0 100644
--- a/windows/winhelp.c
+++ b/windows/winhelp.c
@@ -154,7 +154,7 @@
                lpwh->size, lpwh->command, lpwh->data,
                lpwh->ofsFilename ? (LPSTR)lpwh + lpwh->ofsFilename : "");
 
-    return SendMessageA(hDest, WM_COPYDATA, hWnd, (LPARAM)&cds);
+    return SendMessageA(hDest, WM_COPYDATA, (WPARAM)hWnd, (LPARAM)&cds);
 }