Daniel Berger wrote:

> When building Ruby from source, how does it know to skip over extensions 
> like win32ole on non-Windows platforms?

That's what automake's configure is for. Enter ./configure --help, then look in 
ext/Setup.nt. ./configure, roughly speaking, turns on the packages it can find, 
and the ext/Setup.* files then turn them off.

-- 
   Phlip