error compiling c++ sample - old creepy gcc bug spotted

[Volodymyr Kostyrko]

Hi all.

There goes a reduced test case that compiles smoothly on FreeBSD 
10/CentOS 6 but fails on DragonFly 3.8.1 / master:

#include <string>

int main()
{
     std::to_string(0);
     return 0;
}

The problem is described at 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52015 and it states that 
this is due defining _GLIBCXX_HAVE_BROKEN_VSWPRINTF somewhere. But I 
can't find where it can be defined in /usr/src. Can someone help me 
debug this issue?

-- 
Sphinx of black quartz judge my vow.