Undocumented ABI changes of std::function between GCC-4 and GCC-5/6/7/8/9, how to make a .so working with devtoolset-4/6/7/8/9?

with _GLIBCXX_USE_CXX11_ABI=0 std::function of GCC-4 is different of GCC-5 and follwing versions.

The following code show you the fact:

==> lib.cc <==

#include <functional>

std::function<int(const void*p)> holder;

int run_holder(const void *p)
{
    return holder(p);
}

==> main.cc <==

#include <stdio.h>
#include <functional>

extern int run_holder(const void*p);
extern std::function<int(const void*p)> holder;

int foo(const void* p)
{
    printf("p=%p\n", p);
    return 0;
}

int main()
{
    holder = foo;
    foo((void*)0x12345678);
    holder((void*)0x12345678);
    run_holder((void*)0x12345678);
}

==> make.sh <==

#!/bin/bash
GCC4=/usr/bin/g++
GCCN="scl enable devtoolset-5 -- g++"

$GCC4 -std=c++11 -c -g lib.cc -shared -o libfoo.so &&
$GCCN -std=c++11 -L. -lfoo -g main.cc -o a.out &&
LD_LIBRARY_PATH=. ./a.out