Since more and more information in now available through the CPU
registers, those require DLV_HOST access to be a bit better handled
than it is...

- in backtraces, (void) functions should be listed with '()' as arguments instead of ''
- factorized code for diplaying information about a local/parameter
- fixed a couple of bugs here
- rewrote format specifiers for print commands (do no waste space for padding data)
- added support for new wine's dbghelp extension for local/parameter
  variables being out of scope

They are stored internally as offsets to the start of the function
which embeds the block.

dbghelp: We can now remove the default name prefix as all the non conforming cases have been eliminated.

Got rid of dwarf2_find_name which is now useless.

(except for parameters which are converted into local variables).

Rewrote dwarf2_find_attribute so that it takes into account the
abstract origin information when available.

A+

(removed this feature for UDTs, structures' fields, enums, typedefs, compilands)

Make use of it to store the frame information for a dwarf function
(either because frame's location is a location list, or because one of
the function's variables is not properly computed at parse time).

dbghelp: Added infrastructure to compute variable location at runtime (as opposed to debug info parse time).

Use it to send the variables depending on not known frame register at parse time.
Made just a stub for the location computation function for dwarf2.

dbghelp: Use the location info structure thoughout the code to handle the location of a data variable.

Make use of it in dwarf.c to handle correctly variable location computation.
Split code to handle both location with parse time computation
(current code) and yet to come run-time computation

This makes the code simpler to read, a bit more efficient, and
furthermore it'll be needed in future patches.