&{..$..} => ${eval ${call ..$$..}}
(matches { } pairs to find the end)
content is $-doubled (unless it contains &$- to turn that off)
+ cf &(...), see "Convenience syntax for eval", below.
Together &:macro and &${...} provide a more reasonable macro facility
than raw make. They solve the problem that make expansions cannot
or places where this might imply $-quadrupling. (There is no way to
get $-quadrupling.)
+Convenience syntax for eval
+- - - - - - - - - - - - - -
+
+&(thing => $(call thing
+&( thing => $(call thing
+ and specially:
+&(&lc => $(call sub_dir_lc or $(call TOP_lc
+&( &lc => $(call sub_dir_lc or $(call TOP_lc
+ even though lc would normally be thought a filename
+
+Unlike &{...}, this does not involve any dollar-doubling.
+
Invocation, "recursive" per-directory targets
---------------------------------------------