1.9.2

CHANGES:

• Put back library variants in development mode. We discovered a
  serious unexpected issue and we might need to adjust the design of
  this feature before we are ready to commit to a final version. Users
  will need to write (using library_variants 0.1) in their
  dune-project file if they want to use it before the design is
  finalized. (#2116, @diml)

• Forbid to attach a variant to a library that implements a virtual
  library outside the current project (#2104, @rgrinberg)

• Fix a bug where dune install would install man pages to incorrect
  paths when compared to opam-installer. For example dune now
  installs (foo.1 as man1/foo.1) correctly and previously that was
  installed to man1/man1/foo.1. (#2105, @aalekseyev)

• Do not fail when a findlib directory doesn't exist (#2101, fix #2099, @diml)

• [coq] Rename (coqlib ...) to (coq.theory ...), support for
  coqlib will be dropped in the 1.0 version of the Coq language
  (#2055, @ejgallego)

• Fix crash when calculating library dependency closure (#2090, fixes #2085,
  @rgrinberg)