TR1 and standard headers

[Matt Austern]

My apologies if Benjamin or someone else has already answered this, 
but...

Have we decided on a policy yet for TR1 components that modify standard 
headers?  TR1 defines extensions to <functional>, <utility>, and 
probably other headers that aren't coming to mind right now.  (Not 
counting the C99 compatibility stuff, which affects all of the <c...> 
headers.)

I think we've got two sensible choices: edit the standard headers and 
control the extensions with a macro, or put shadow headers in 
include/tr1.

			--Matt