Log message:
Drop superfluous PKG_DESTDIR_SUPPORT, "user-destdir" is default these days.
Mark packages that don't or might probably not have staged installation.

Log message:
Import tnt-3.0.12 as wip/tnt.

The Template Numerical Toolkit (TNT) is a collection of interfaces and
reference implementations of numerical objects useful for scientific
computing in C++. The toolkit defines interfaces for basic data
structures, such as multidimensional arrays and sparse matrices, commonly
used in numerical applications. The goal of this package is to provide
reusable software components that address many of the portability and
maintenance problems with C++ codes.
TNT provides a distinction between "interfaces" and \ 
"implementations" of
TNT components. For example, there is a TNT interface for two-dimensional
arrays which describes how individual elements are accessed and how
certain information, such as the array dimensions, can be used in
algorithms; however, there can be several implementations of such an
interface: one that uses expression templates, or one that uses BLAS
kernels, or another that is instrumented to provide debugging
information. By specifying only the interface, applications codes may
utilize such algorithms, while giving library developers the greatest
flexibility in employing optimization or portability strategies.