Compilation issue on FreeBSD with clang 16

[videlec]

In file included from ppl/linear_algebra.cpp:799:
/usr/local/include/ppl.hh:101797:33: error: no member named 'mem_fun_ref' in namespace 'std'; did you mean 'widen_fun_ref'?
  pairwise_apply_assign(y, std::mem_fun_ref(&D::meet_assign));
                           ~~~~~^
/usr/local/include/ppl.hh:96540:1: note: 'widen_fun_ref' declared here
widen_fun_ref(void (PSET::* wm)(const PSET&, unsigned*)) {
^
/usr/local/include/ppl.hh:103755:57: error: no member named 'mem_fun_ref' in namespace 'std'; did you mean 'widen_fun_ref'?
                          Det_PSET::lift_op_assign(std::mem_fun_ref(&PSET::intersection_assign)));
                                                   ~~~~~^
/usr/local/include/ppl.hh:96540:1: note: 'widen_fun_ref' declared here
widen_fun_ref(void (PSET::* wm)(const PSET&, unsigned*)) {
^
/usr/local/include/ppl.hh:103763:57: error: no member named 'mem_fun_ref' in namespace 'std'; did you mean 'widen_fun_ref'?
                          Det_PSET::lift_op_assign(std::mem_fun_ref(&PSET::time_elapse_assign)));
                                                   ~~~~~^
/usr/local/include/ppl.hh:96540:1: note: 'widen_fun_ref' declared here
widen_fun_ref(void (PSET::* wm)(const PSET&, unsigned*)) {
^
3 errors generated.

Can be work around by setting the compiler option -std=c++14 in CFLAGS.

The same problem seems to happen with PPL itself.