How can I print variables im using in makefiles?

Shell Programming and Scripting
1

for example in my make file im building path from env variables and string but need to see what is did
what is the best way to print the result?
say I have in my Makefile :
exec_prefix = $(RUN_ENV_LOCAL)/apache
and I will like to print the exec_prefix value , how can it be done ?

2 
<tab> @echo "$(exec_prefix)"