export vs $(origin )

[Jan Beulich]

Hello,

with documentation stating

"As a convenience, you can define a variable and export it at the same
 time by doing: ..."

It being merely a convenience, is it really intended for "export"
without any assignment done at the same time to change the origin of a
previously undefined variable from "undefined" to "file"? It doesn't
change "default" to "file" for a variable with a default value, for
comparison.

As to the use case - to be able to determine whether a variable has
been given a non-default value, and for such a check to be independent
of whether
- -R was passed to make
- export lives ahead or after the check
a change in behavior would seem to be needed, as such a check can,
afaict, only sensibly check for "undefined" and "default".

FAOD I checked up to 4.3, but not any newer development version of make.

Thanks, Jan