&:<directive> <args>....
recognised at start of line only (possibly after lwsp)
- args are processed for &
&:include filename filename should usually be [&]foo.sd.mk
&:-include filename tolerate nonexistent file
Notably
NEWQUOTENEWQUOTE => NEWQUOTENEWQUOTE
NEWQUOTE\NEWQUOTE => NEWQUOTE
+ NEWQUOTE\$ => $
NEWQUOTE:changequote & set escape back to &
&TARGETS_things