bootstrap:unify: unify_generics(): fix for non-tentative case
lib/n/builtins_string: Stringbuf: Pr, Say methods
lib/n/builtins_string: all `String are `Show
bootstrap/cprinter: attribute((weak)) should be on data definitions
lib/n/builtins_string; Stringbuf.Vpr: fix printing of sep with (null) args
lib/n/builtins: Reverse_index_iterator: fix bug
bootstrap: use a/a.n instead of a/module.n
Accept recent test output changes
t00/automagicderef: fix after change in RHS term for arithmetic shifts
t00/float: fix test
bootstrap/topdeps: reference fields do not introduce inline struct deps
bootstrap:ncc0: improve support for clang on generated code
bootstrap: reduce mess relative to Slice init and copy

Slice copy operations, and Slicebuf init operations (from Slice
literals) are optional operations, only available if t isa `Copyable or
t isa `Trivial_copy.

We don't yet have support for optional operation, yet we need them. So
we cheat, and since ncc0 is a bit of a pushover...
trun,taccept,tdiff: store and use exit status code
bootstrap: avoid creating pristine copies in instances
bootstrap:common: timeit utilities
bootstrap: shallower deepcopy for tentative instances: stop at BLOCK
bootstrap: add more timeit points
bootstrap: module_hash_ptr(): fix incorrect hashing
bootstrap:catchup: minimize work for tentative instances

It never makes sense to go beyond the last forward pass.