vere64

[matthew-levan]

Cribbed from #794.

This PR introduces 64-bit Vere. The principle changes involved have to do with the introduction of a new type, c3_n, which is 32 bit or 64 bit depending on if it was compiled with -DVERE64.

The following work still needs to be done:

• define final typedefs, update usages accordingly
• every appearance of _tmp in pkg/noun (excluding pkg/noun/jets) (~800 locations)
  • trace.{c,h}
  • ship.{c,h}
  • nock.h
  • version.h
  • imprison.{c,h}
  • jets.{c,h}
  • allocate.{c,h}
  • retrieve.{c,h}
  • *_tests.c
• every appearance of _tmp in pkg/noun/jets
• look at diff of pre and post VERE64 compilation with -Wconversion flag. Investigate every instance.
• run with llvm addr sanitizer, ubsan
  • found issues with asan and ubsan as of 61fc9de (lmdb addressed in vere: fix some undefined behavior #820)
• audit every jet
• migrations: bidirectional (use MSB of version tag to mark if vere64 or not? maybe also add metadata for pointer compression)
• integrate Joe's page based allocator
• new rsignal_setjmp/longjmp may have volatility problems (talk to Joe. maybe use atomics?)
• pkg/vere/noun-tests is completely broken
  • ensure noun tests make sense/are worth having
• every appearance of _tmp in any other subdirectory (~1000 locations)
• c3_w_clz, ctz, pc occurrences (we should change current occurrences to _tmp as we did with u3r_word, etc and go through them
• c3_etch_word, c3_sift_word occurrences (also change to _tmp)
• make sure everything works (C tests and hoon tests included) still for vere32
• revendor murmur3 with a size_t len
  • hoon: murmur3 revendor urbit#7186
  • mug: murmur3 revendor with size_t to support 64-bit #842
• test really big nouns in ames/fine/mesa
• the event log and other lmdb state should not need migration. we should double check lmdb.c, disk.c
• there's a lot of bloq size related things in the jets that could be changed to greater than 32 for the 32 bit case
• (mug .(eny 0, now 0)) equality test for fakezods booted in 32-bit and 64-bit modes