offline elfutils processing committed

["Frank Ch. Eigler" <fche at redhat dot com>]

Hi -

A big commit went in just now, as a holloween prank no doubt.  Some
dude named "fche" finally checked in code to switch to elfutils'
"offline" processing mode, which allows generation of instrumentation
for kernels where the specific list of modules and their addresses
need not be known until run-time.  This involves a somewhat longer
elaboration pass, since all possibly-needed modules' dwarf data are
brought in, not just those that are loaded right now on the
translator's host.

This part needs one more bit of code from staprun (hunt) to pass a
module/section/address table to the module.  A limited mockup is
present in the generated code and should be replaced shortly.
(dwarf_derived_probe_group::emit_module_decls).

The new code also significantly improves the code generated for
scripts involving many probes.  (It also drastically simplifies the
translator's own code for this.  Partly unraveling this mess took lots
of time.)  All this builds on but replaces the earlier "probe groups"
effort.  You may find first-time compile time for complex scripts to
be noticeably shorter.  Since it is compatible with the recent caching
code, second-time compile time is near-zero.

Just to finally commit this piece of work, I just disabled some
previously working but little-used code.  I'll plop them back in
shortly: the benchmarking option, and perfmon/mark based probes.

- FChE

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