I have two ideas for you:
First, run something like:
make -n bin/progA LINK.cc='OBJECTS:' | grep ^OBJECTS:
then capture the output. You'll have to get rid of the -o
etc. by hand from the results though.
The other idea is to run "make -pn" to get a copy of make's database, and parse that with grep or whatever.
The advantage to these vs. just going through the makefile directly is that any variables, etc. will be expanded for you by make.