CHANGES:

- Do not fail if the output of `ocamlc -config` doesn't include
  `standard_runtime` (ocaml/dune#1326, @diml)

- Let `Configurator.V1.C_define.import` handle negative integers
  (ocaml/dune#1334, @Chris00)

- Re-execute actions when a target is modified by the user inside
  `_build` (ocaml/dune#1343, fix ocaml/dune#1342, @diml)

- Pass `--set-switch` to opam (ocaml/dune#1341, fix ocaml/dune#1337, @diml)

- Fix bad interaction between multi-directory libraries the `menhir`
  stanza (ocaml/dune#1373, fix ocaml/dune#1372, @diml)

- Integration with automatic formatters (ocaml/dune#1252, fix ocaml/dune#1201, @emillon)

- Better error message when using `(self_build_stubs_archive ...)` and
  `(c_names ...)` or `(cxx_names ...)` simultaneously.
  (ocaml/dune#1375, fix ocaml/dune#1306, @nojb)

- Improve name detection for packages when the prefix isn't an actual package
  (ocaml/dune#1361, fix ocaml/dune#1360, @rgrinberg)

- Support for new menhir rules (ocaml/dune#863, fix ocaml/dune#305, @fpottier, @rgrinberg)

- Do not remove flags when compiling compatibility modules for wrapped mode
  (ocaml/dune#1382, fix ocaml/dune#1364, @rgrinberg)

- Fix reason support when using `staged_pps` (ocaml/dune#1384, @charlesetc)

- Add support for `enabled_if` in `rule`, `menhir`, `ocamllex`,
  `ocamlyacc` (ocaml/dune#1387, @diml)

- Exit gracefully when a signal is received (ocaml/dune#1366, @diml)

- Load all defined libraries recursively into utop (ocaml/dune#1384, fix ocaml/dune#1344,
  @rgrinberg)

- Allow to use libraries `bytes`, `result` and `uchar` without `findlib`
  installed (ocaml/dune#1391, @nojb)

- Take argument to self_build_stubs_archive into account. (ocaml/dune#1395, @nojb)

- Fix bad interaction between `env` customization and vendored
  projects: when a vendored project didn't have its own `env` stanza,
  the `env` stanza from the enclosing project was in effect (ocaml/dune#1408,
  @diml)

- Fix stop early bug when scanning for watermarks (ocaml/dune#1423, @diml)