Via [Wayback/Archive] Crowbarring Windows 95 into Windows NT with CAPITALS • The Register refers a nice trick that I have used in various case-codebases as well.
On case sensitive environments the casing method is easy no matter if you use macros or just regular identifiers.
On case insensitive environments, prepending or appending soemthing like an underscore (_) works just as well.
The trick referred to is in a section of [Wayback/Archive] How did the Windows 95 user interface code get brought to the Windows NT code base? – The Old New Thing:
The Wiert Corner - irregular stream of stuff 