XP_WIN32 is a synonym for XP_WIN. It's not used much. We should remove it.
But there's a wrinkle with NSS -- the meanings of XP_WIN and XP_WIN32 are subtly different when building NSS outside of Firefox's build system.
Within Firefox's build system:
- XP_WIN, XP_WIN32, WIN32, and _WINDOWS are defined on all Windows builds
But secport.h within NSS does the following:
- defines XP_WIN if _WINDOWS is defined
- So it's always defined within Firefox's build system
- Otherwise, I'm not sure when _WINDOWS is defined
- defines XP_WIN32 if _WIN32 or WIN32 is defined
- True on any Win32 machine
We can easily change all occurrences of XP_WIN32 within Firefox to XP_WIN,
excluding the ones in NSS.
As for NSS, it seems like things could be cleaned up, but I'm not certain how.