If by configure release/build, you mean you only need one config per makefile, then it is simply a matter and decoupling CC and CFLAGS:
CC=g++ -g3 -gdwarf2 $(CFLAGS)
Depending on whether you can use gnu makefile, you can use conditional to make this a bit fancier, and control it from the command line:
DEBUG ?= 1
ifeq (DEBUG, 1)
$(CC) -c $< -o $@ $(CFLAGS)
and then use:
If you need to control both configurations at the same time, I think it is better to have build directories, and one build directory / config.