utils.py: helper function for optional include files
The main intention is to provide easy-to-use and read helper functions
for including files only when certain distro features are
set. Functionally they are the same as bb.utils.contains and
bb.utils.contains_any.
Distro features are part of the base configuration and thus safe to
use for conditional inclusion in recipes and bbappends, in contrast to
recipe variables which might still change during parsing. Therefore
the check is limited to DISTRO_FEATURES. This is the reason for having
this in OE-core instead of bitbake.
Default values are set so that no redundant parameters have to be
passed for conditional includes. As a secondary usage, the functions
can also be used in boolean checks.
Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
