gen_ver.pl: add OS version to the list of defines

Signed-off-by: Steven Noonan <steven@uplinklabs.net>

Created by  Steven Noonan  on October 18, 2009
UNNAY5ZO32Q3KC37FMLGDX7GHUKMGKW7XF63F3HTVGU53XZTA6KAC
Change contents