bootstrap: rename typ_pretty_name() to pptyp()
bootstrap: rename printer_tree() to pptree()
Accept recent test output changes
Rename 'Size' to 'Uint', and 'Ssize' to 'Int'
lib/n/math: export functions

They were missed when export was replaced by uppercase for export.
Only integer types with a well-defined bit size are `Bitwise

Since Int and Uint bit size is platform dependent, we don't want to
encourage bitwise operations on them that are usually dependent on the
that bit size. While we could insert runtime checks to prevent
overflow (for instance), we might as well get people to use sized
integer types.
lib/n/builtins: Use Likely in Assert/etc., make them inline
bootstrap:import: fix import '*' (or module import) of 'let' or 'alias'

It was fine when used with named import.
bootstrap:lexer: clarify illegal char message
bootstrap:passfwd: validate_genargs_types: handle DEFINCOMPLETE

For instance, in the following case

	fun returns_tuple = Error, Int
		return OK, 0

'OK' is typed as a DEFINCOMPLETE{"OK"}. When building the return value,
we're typing against (Tuple_2 t1:`Copyable t2:`Copyable).

validate_genargs_types() now adds `Copyable so that:
	DEFINCOMPLETE{"OK" `Copyable}
bootstrap:nodes: node_move_content(): must clear 'expected' field of the dst

When moving content over, both the 'src' and 'dst' shouldn't be excepted
anymore.
bootstrap:ssa: step_ssa_convert_shallow_catchup

step_ssa_convert() cannot work on excepted nodes. In the operator
function rewrite:
	0 + 1 -> Operator_plus @0 @1
0 and 1 are excepted. So we need to come after that step and double
check.
bootstrap:cprinter: do not print generic guard when no decl or def is printed

This kind of codegen bug is particularly problematic when this is done
for symbols otherwise declared weak. Then a missing definition in the
generated C code is not a compilation error but leaves a 0 for the
function address in the assembly.
bootstrap:lir: fix EXCEP rewriting: must honor 'before'
bootstrap:cprinter: print_init_array: fix (must be related to recent SSA changes?)
Uppercase Drop and Fatal: they're regular functions, not builtin keywords
Rationalize number types and conversion operations

Use clearer names, and make available bitwise, unsafe and checked
conversions for non-trivial cases.
bootstrap: introduce overflow arithmetic operators

Overflow checks for the standard operators are not implemented yet.
bootstrap: support '_' in number literals

They are simply ignored
	1_000_000
	0xffff_ffff