[makefile] How to print out a variable in makefile

You could create a vars rule in your make file, like this:

dispvar = echo $(1)=$($(1)) ; echo

.PHONY: vars
vars:
    @$(call dispvar,SOMEVAR1)
    @$(call dispvar,SOMEVAR2)

There are some more robust ways to dump all variables here: gnu make: list the values of all variables (or "macros") in a particular run.