As far as I know there's no generally satisfying way to ask Make to
"tell me everything about this variable" (I'd be fine with filtering
trace output for all variables).
For example I mostly like this trick rule:
echo-%: ; @echo '$($*)'
but it could be misleading if variables have been used during Make's
first pass and then changed (it would be nice if there was some way to
make variables sort of immutable, but that's a different subject) or
if target-local variables are being used.
The many answers here show the appetite for finding out about variables:
https://stackoverflow.com/questions/16467718/how-to-print-out-a-variable-in-makefile
A variety of different approaches are represented there, but none of
them cover all situations.
I think --debug would be the place for some general solution. Thoughts?
Britton
