private interface no more public

[Stathis Kamperis <ekamperi%gmail.com@localhost>]

Hi jmmv et al :)

With the advent of atf 0.11, If I'm right, the private headers are no
longer installed. I was using them to implement some helper functions.
See for example, here:

http://gitweb.dragonflybsd.org/~beket/mathlib.git/blob/master:/subr_atf.c

Since these private headers are gone for real, could we perhaps add
support for the get_config_var_as_{bool, long}() functions ?

Best regards,
Stathis