Unable to build 0.17.1 on macos 15.5 due to `-mpopcnt`

[dotcarmen]

seems to have been previously fixed in #178 but I still get the clang error about -mpopcnt 😬

#=== ERROR while compiling base.v0.17.1 =======================================#
# context     2.3.0 | macos/arm64 | ocaml.5.3.0 | https://opam.ocaml.org#a263eb47bd23b8c5e3555052b1f086fe933eebde
# path        ~/.opam/default/.opam-switch/build/base.v0.17.1
# command     ~/.opam/opam-init/hooks/sandbox.sh build dune build -p base -j 9
# exit-code   1
# env-file    ~/.opam/log/base-61571-df6a5f.env
# output-file ~/.opam/log/base-61571-df6a5f.out
### output ###
# [...]
# (cd _build/default/src && /usr/bin/cc -O2 -fno-strict-aliasing -fwrapv -pthread -D_FILE_OFFSET_BITS=64 -fdiagnostics-color=always -D_LARGEFILE64_SOURCE -mpopcnt -g -I /Users/carmen/.opam/default/lib/ocaml -I /Users/carmen/.opam/default/lib/ocaml_intrinsics_kernel -I /Users/carmen/.opam/default/lib/sexplib0 -I ../hash_types/src -I ../shadow-stdlib/src -o int_math_stubs.o -c int_math_stubs.c)
# clang: error: unsupported option '-mpopcnt' for target 'arm64-apple-darwin24.5.0'
# File "src/dune", line 19, characters 46-56:
# 19 |   (names bytes_stubs exn_stubs int_math_stubs hash_stubs obj_stubs am_testing)
#                                                    ^^^^^^^^^^
# (cd _build/default/src && /usr/bin/cc -O2 -fno-strict-aliasing -fwrapv -pthread -D_FILE_OFFSET_BITS=64 -fdiagnostics-color=always -D_LARGEFILE64_SOURCE -mpopcnt -g -I /Users/carmen/.opam/default/lib/ocaml -I /Users/carmen/.opam/default/lib/ocaml_intrinsics_kernel -I /Users/carmen/.opam/default/lib/sexplib0 -I ../hash_types/src -I ../shadow-stdlib/src -o hash_stubs.o -c hash_stubs.c)
# clang: error: unsupported option '-mpopcnt' for target 'arm64-apple-darwin24.5.0'
# (cd _build/default && /Users/carmen/.opam/default/bin/ocamlopt.opt -w -40 -g -I src/.base.objs/byte -I src/.base.objs/native -I /Users/carmen/.opam/default/lib/ocaml_intrinsics_kernel -I /Users/carmen/.opam/default/lib/sexplib0 -I hash_types/src/.base_internalhash_types.objs/byte -I hash_types/src/.base_internalhash_types.objs/native -I shadow-stdlib/src/.shadow_stdlib.objs/byte -I shadow-std[...]
# File "src/array.ml", line 399, characters 28-75:
# 399 |       result := Bool.select ((keep_left_if [@inlined]) (compare x !result)) x !result
#                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# Warning 55 [inlining-impossible]: Cannot inline: Unknown function