[Bug libstdc++/91371] New: std::bind and bind_front don't work with function with call convention

[roland at rschulz dot eu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91371

            Bug ID: 91371
           Summary: std::bind and bind_front don't work with function with
                    call convention
           Product: gcc
           Version: 9.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: roland at rschulz dot eu
  Target Milestone: ---

If a function with call convention function type attribute is passed to
bind/bind_front it fails.

Reproducer:
#include<functional>

int bar(int) __attribute__((ms_abi)); //same with fastcall, thiscall

void test() {
    std::bind(bar, 5)(); //error: function returning a function
    std::bind_front(bar, 5)(); //error: static assertion failed
}

Godbolt showing it works with libc++:
https://godbolt.org/z/3g7Vk7