We create two libraries where one depends on the other. The dependency library
also has more than one src dir.

  $ echo "(lang dune 2.0)" > dune-project
  $ mkdir -p lib1/sub
  $ cat >lib1/dune <<EOF
  > (include_subdirs unqualified)
  > (library (name lib1))
  > EOF
  $ touch lib1/sub/foo.ml
  $ touch lib1/bar.ml
  $ mkdir lib2
  $ cat >lib2/dune <<EOF
  > (library
  >  (name lib2)
  >  (libraries lib1)
  >  (modules ()))
  > EOF

  $ opam_prefix="$(ocamlc -where)"
  $ export BUILD_PATH_PREFIX_MAP="/OPAM_PREFIX=$opam_prefix:$BUILD_PATH_PREFIX_MAP"

  $ dune build lib2/.merlin-conf/lib-lib2
  $ dune ocaml merlin dump-config --format=json $PWD/lib2 | jq -r '
  >   include "dune";
  >   merlinEntry("Lib2")
  >   | merlinJsonEntryWithConfigNames(["STDLIB", "S", "UNIT_NAME"])'
  Lib2: _build/default/lib2/lib2
  ["STDLIB","/OPAM_PREFIX"]
  ["S","$TESTCASE_ROOT/lib1"]
  ["S","$TESTCASE_ROOT/lib1/sub"]
  ["S","$TESTCASE_ROOT/lib2"]
  ["UNIT_NAME","lib2"]
  Lib2: _build/default/lib2/lib2.ml-gen
  ["STDLIB","/OPAM_PREFIX"]
  ["S","$TESTCASE_ROOT/lib1"]
  ["S","$TESTCASE_ROOT/lib1/sub"]
  ["S","$TESTCASE_ROOT/lib2"]
  ["UNIT_NAME","lib2"]
