remove features that we don't need so as to make the tree as
simple as possible to descend
in particular if we're just pinging the HAL layer for some simple
constants we don't have to pull in the hairball of std targets
this is a common api problem because yes, while arg1 is strictly
the second item, previously arg0 was hidden and in the argument
list arg1 took the first place not the second. so i make this
mistake a lot...