[99s-extend] Cowboy Makefile

[Grzegorz Junka]

Hi,
I understand the move away from Rebar but I'd like to see the project to 
be still Rebar-compatible. Would that be a problem? Mainly I am thinking 
about dependencies. The Cowboy Makefile assumes that Ranch is in its 
deps folder. If Cowboy is a part of a bigger application, and most often 
it will be in such a role rather than a standalone application, then all 
dependencies should be kept in one place. In that case it would be the 
main project's deps folder, not Cowboy's deps folder. Can the 
compilation process be split into compiling Cowboy dependencies 
separately from Cowboy itself?

something like:

all: compile-deps compile-cowboy

Then if Cowboy is a dependency itself it may be just compiled without 
the dependency (as it will be compiled when the main project is compiled).