How to know SunOS rev in 'cc'

[Dan Watts]

When compiling a problem under SunOS, is there a symbol defined by the
compiler that can be used to determine the rev of the O/S it's being
compiled on?  I'm trying not to add yet another -dxxxx to my cc line.  I
need to be able to compile the same program on both SunOS 4.0.3 and SunOS
4.1

Any pointers would be apreciated.

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