pkgsrc namespaces (was: BLAS in pkgsrc: present and future)

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

> not necessarily clearly mapped to variable namespaces
There seems to be a general lack of a notion of namespaces.

When importing something into pkgsrc, I'm often asking myself whether 
I'm allowed to use a geeric variable name (EGDIR, DOCDIR, FEATURES, EDITOR) 
or if they are used by pkgrsc's infrastucture (or worse: will be used by a 
future version of the infrastructure).

I also sometimes, when reading an existing Makefile for refence, as myself 
whether some generic sounding variable used there is set by the 
infrastructure or some Makefile.common, options.mk or the like.

It would help to have some per-package/user namespace. Things easily become 
unreadable if I prefix everything with ICINGAWEB2_ or LUA_STD__DEBUG_.