All backends emit nothing for Phis and be_Keeps, so set this centrally.

- The backends can simply perform the finish_graph() steps in the emit()
  phase.

It has been empty for nearly all systems. People who used to put stuff
in config.h can still create a config.h on their own and inject
-include (gcc) or /FI (msvc) into their CPPFLAGS.

Just state the copyright and the project the files belong to. You can
then find the COPYING file for the whole project.

beemit: Provide be_emit_node(), which merges the (almost) identical node emit functions of the backends.

Also use one common be_emit_nothing().

Remove now redundant (and sometimes wrong) location info from the panic messages.

Also factor out code that emits the label and comment at the beginning
of a basic block.

- We now always output dwarf3 so we can use DW_OP_call_frame_cfa and avoid
  construction location lists, but just reuse the callframe info lists.
- Backends have to emit debug info as callframe calculation changes:
  The ia32 backend has a preliminary implementation which assumes esp
  offset of frame_type_size at the beginning of a block (currently
  always true), the no-omit-fp mode assumes ebp relative addressing
  (which is correct except for the prolog/epilogue insns)

The opcode list was a member of irprog before which wasn't really
handled consistently. Also make sure opcodes are properly freed at
ir_finish().

This was an odd convention from the past, there's no need for it
anymore.

This tries to get the names in a consistent format. We basically have 2
views on register allocation/constraints now:

1) Register Requirements and Assigments are per-instruction. Each
   instruction has requirements on its inputs and outputs, register get
   assigned for outputs of an instruction (assignment is an attribute of
   an instruction, not of the Proj-nodes).
   The internal datastructures model this form!

   The functions here have the form:
     arch_get_irn_register_req_in(node, input_nr)
     arch_get_irn_register_in(node, input_nr)
     arch_get_irn_register_req_out(node, output_nr)
     arch_set_irn_register_out(node, output_nr, register)

2) Register Requirements and Assignments are on firm-values. This view
   allows to query/assign requirements and registers at the Proj nodes
   instead of the repsective predecessors.
   This is a convenience interface modeled on top of the other!

   The functions have the form:
     arch_get_irn_register_req(node)
     arch_get_irn_register(node)
     arch_set_irn_register(node, register)

[r28282]

[r28127]

[r27699]

[r27460]

[r27300]

[r27277]

[r27150]

[r27149]

[r26746]

- Add a generic requirements+register+flag dumper to bearch; This avoids all
  backends/benode having their own slightly different dumpers
- Lots of cleanups in the backends along the way

[r26542]