It is sometimes desirable to package debugging information that is a subset of
the original data.  The subset would need to be just enough to run some
systemtap scripts.  One may want to ship just a subset because the full
debuginfo would be proprietary, or just too darn big.

Here's one way to do it:
- let the interesting part of the application be defined by a collection of
systemtap scripts (and the tapsets they use)
- extend systemtap / elfutils to be able to mark all parts of the debugging
files actually used - at as low as a DIE granularity
- develop a tool to take such markings, and excise all unmarked parts of the
debuginfo.  it may be simplest to zero-fill the unused parts, then compress the
resulting file.
- extent systemtap to look for such subsetted debuginfo files in another path,
using elfutils path settings already available