doesn't compile on freebsd #1
Description
#=== ERROR while compiling cpu.2.0.0 ==========================================#
# context 2.0.6 | freebsd/x86_64 | ocaml-base-compiler.4.09.1 | file:///usr/home/travis/build/ocaml/opam-repository
# path /usr/home/travis/.opam/ocaml-base-compiler.4.09.1/.opam-switch/build/cpu.2.0.0
# command /usr/home/travis/.opam/ocaml-base-compiler.4.09.1/bin/dune build -p cpu -j 1
# exit-code 1
# env-file /usr/home/travis/.opam/log/cpu-8809-aa8f74.env
# output-file /usr/home/travis/.opam/log/cpu-8809-aa8f74.out
### output ###
# ocamlc src/cpu_stubs.o (exit 2)
# (cd _build/default/src && /usr/home/travis/.opam/ocaml-base-compiler.4.09.1/bin/ocamlc.opt -g -ccopt -g -ccopt -O2 -ccopt -fPIC -ccopt -Wall -ccopt -pedantic -ccopt -Werror -ccopt -Wno-long-long -ccopt -g -o cpu_stubs.o cpu_stubs.c)
# cpu_stubs.c:24:7: error: unused variable 'w' [-Werror,-Wunused-variable]
# int w = Int_val(which) % numcores; // stay in the space of existing cores
# ^
# cpu_stubs.c:31:7: error: unused variable 'retcode' [-Werror,-Wunused-variable]
# int retcode;
# ^
# 2 errors generated.