adipls should get a USE_ADIPLS build option

[rjfarmer]

Given that building adipls breaks the moment you look at it (well change compiler flags or set things like FFLAGS in your shell), can we get a way to disable building adipls (like we can do with gyre)?

That way i can completely ignore adipls.

[warrickball]

I agree this should be an option but I doubt I'll have time to work on it for a week or so. As it is, ADIPLS doesn't appear to inherit any compiler options from makefile_header, so I presume you can mess around there without consequence? As for FFLAGS, I presume another (temporary) solution is to empty it in the ADIPLS makefiles (i.e. add FFLAGS=) so it can't collide with environment variables.