Driver:

Refactoring:
- eliminate target_architecture.h and replace with stuff in lang_features.h
- redo storage classes: so we can separate real from declared storage class
- create structures for variables and functions, removing the omnipotent declaration

Lexer:
- Add preprocessor code
- proper handling of different file encodings, parsing non-ascii strings
- We could save some space by holding source positions in a separate (somehow
  compressed table) and only storing pointers to it on the AST.

Parser:
- disallow storage class specifiers in struct/union members
- label: declaration; is no valid C99 but we parse it anyway
- add constant folding code (optional, ast2firm already does it)
- Refactor code, so code to handle number values (and strings?) is an own
  module and replacable
- Support some attributes. noreturn, unused, printf, scanf, packed would be
  interesting candidates
- Add columns to source positions
- SourcePositions could be stored selectively on expressions that really need
  them.
- check semantic for functions declared/defined in global scope and declared
  again in a local scope
- print initialisation type_path for initializer errors
- check switches for: double cases, all enums

ast2firm:
- handle non-constant initializers
- output source file positions for panics...
- handle bitfield members with 0 correctly (standard says they finish the
  current unit)

Missing Errors:
* check switches for double cases

Missing Warnings:
* dead assignments (int x = 5; x = bla(); -> dead assignment at x = 5;)
* unused label
* check switches for all enums values


Spec-Status:
(only test datasets tried yet)
164.gzip:    works
175.vpr:     works
176.gcc:     not ok
181.mcf:     works
186.crafty:  works (~though an asm is replaced with a stub)
253.perlbmk: not ok
254.gap:     not ok
255.vortex:  works
256.bzip2:   works
300.twolf:   works