Finally, define FOO_SRC and FOO_HDR to contain both
FOO_PLATFORM_{SRC,HDR} and FOO_{SRC,HDR} (see NET_SRC definition for an
example).
- * Add FOO_HDR to ALL_HEADERS
+ * Add FOO_HDR to ALL_HEADERS (or ALL_BASE_HEADERS if wxFoo is not GUI
+ component).
(You can apply different approaches to HDR and SRC variables, if e.g.
headers are all common but sources are not.)