Attached is a cpp+sed template for generating an "options.h" file
indicating which POSIX option groups the implementation claims to
support. Option groups which are mandatory, obsolete, or deal with
utilities rather than system interfaces are not included, but could be
added. The resulting macros are the same as the standard ones in
unistd.h but with the leading underscores removed. The motivation is
to be able to test for option groups without including unistd.h, for
tests where unistd.h would possibly interfere with what's being
tested.

Rich