Add phony targets prerequisites to .PHONY immediately before the target declaration

[dpordomingo]

It seems to be a general recommendation:

Add each phony target as a prerequisite of .PHONY immediately before the target declaration, rather than listing all the phony targets in a single place.

sources:
http://style-guides.readthedocs.io/en/latest/makefile.html
http://clarkgrubb.com/makefile-style-guide#phony-targets