2 - eliminate target_architecture.h and replace with stuff in lang_features.h
5 - Add preprocessor code.
6 - We could save some space by holding source positions in a separate (somehow
7 compressed table) and only storing pointers to it on the AST.
10 - add constant folding code (optional, ast2firm already does it)
11 - Refactor code, so code to handle number values (and strings?) is an own
13 - Add columns to source positions
14 - SourcePositions could be stored selectively on expressions that really need
16 - check semantic for functions declared/defined in global scope and declared
17 again in a local scope
18 - for errors relating to function argument, print number of argument
19 - print initialisation type_path for initializer errors
22 - output source file positions for panics.
25 - goto over VLA declarations
28 - dead assignments (int x = 5; x = bla(); -> dead assignment at x = 5;)
31 - go through gcc manual and emulate all the gcc flags...