Is there any possibility to use the same Makefile in CentOS and FreeBSD?

Unfortunately, in some old FreeBSD environments I can't use "gmake", so I need to write a Makefile which will work with FreeBSD make also. And the last problem I can't solve - use shell commands, for example, I need to get full path to Python executable:

PYTHON := $(shell which python2.7 || which python) 

But FreeBSD make simply ignores this.

test: echo == $(PYTHON) == 

Then I run make test:

$ make test echo == == == == 

Can anyone help, please?

Update #1: To those who can't read closely and accidentally downvotes the question:

Whole test script:

PYTHON != which python2.7 || which python test: $(PYTHON) -c 'print "hello world"' 

Run on FreeBSD:

make /usr/bin/python -c 'print "hello world"' hello world 

Run on CentOS:

make test_make:1: *** missing separator. Stop. 

And if I use command $(shell ...) it works on CentOS and doesn't work on FreeBSD. So, is there any solution without gmake?

Update #2: Eventually I found solution (put command in backticks):

PYTHON ?= `which python2.7 || which python` 

I don't know why it prints itself:

make `which python2.7 || which python` -c 'print "hello world"' hello world 

But it works! You can use it, guys :)