Current opam package does not install

[bruceg]

Running opam install hack_parallel results in this:

[ERROR] The compilation of hack_parallel.1.0.1 failed at "dune build -p hack_parallel -j 15 @install".

#=== ERROR while compiling hack_parallel.1.0.1 ================================#
# context     2.1.2 | linux/x86_64 | ocaml.4.13.1 | https://opam.ocaml.org#9ecf8bc3
# path        ~/.opam/default/.opam-switch/build/hack_parallel.1.0.1
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p hack_parallel -j 15 @install
# exit-code   1
# env-file    ~/.opam/log/hack_parallel-169965-80627c.env
# output-file ~/.opam/log/hack_parallel-169965-80627c.out
### output ###
# [...]
# Warning 69 [unused-field]: record field slave_pid is never read.
# (However, this field is used to build or mutate values.)
#     ocamlopt src/interface/.memory.objs/native/memory.{cmx,o}
# File "src/interface/memory.ml", line 15, characters 2-25:
# 15 |   minor_heap_size: bytes;
#        ^^^^^^^^^^^^^^^^^^^^^^^
# Warning 69 [unused-field]: record field minor_heap_size is never read.
# (However, this field is used to build or mutate values.)
#        ocaml scripts/get_build_id.c (exit 2)
# (cd _build/default/scripts && /home/aurbuild/.opam/default/bin/ocaml -I scripts -w -3 unix.cma gen_build_id.ml get_build_id.c)
# Failed git rev-parse: fatal: not a git repository (or any parent up to mount point /)
# Exception: Unix.Unix_error(Unix.EACCES, "create_process", "hg")

It appears that the install process is trying to use git to get a revision ID, but there is no repository set up.