CPPFLAGS.SunOS?

[Georg Schwarz <georg.schwarz%freenet.de@localhost>]

An handy feature of pkgsrc is the option to define OS-specific  
compiler flags, e.g. CFLAGS.SunOS.
Where exactly do I find the relevant code so I can expand that to  
CPPFLAGS as well?
Or is there a reason not to suipport somethig like CPPFLAGS.SunOS?
Does the pkgsrc documntation mention the option of OS-specific  
compiler and linker flags?
--
Georg Schwarz    http://home.pages.de/~schwarz/
georg.schwarz%freenet.de@localhost  +49 151 11559652