Added a WINE_NO_UNICODE_MACROS define to allow Winelib apps to switch
off the Unicode macros too.

diff --git a/include/ocidl.idl b/include/ocidl.idl
index fbdb00d..8cfaf5e 100644
--- a/include/ocidl.idl
+++ b/include/ocidl.idl
@@ -514,7 +514,7 @@
 {
     typedef IProvideClassInfo *LPPROVIDECLASSINFO;
 
-cpp_quote("#ifdef __WINESRC__")
+cpp_quote("#ifdef WINE_NO_UNICODE_MACROS")
 cpp_quote("#undef GetClassInfo")
 cpp_quote("#endif")