[Bug libstdc++/108288] Deadlock when using -fno-elide-constructor + -D_GLIBCXX_DEBUG=1 + -std=c++11

[redi at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108288

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This was my reproducer, although it doesn't deadlock without the hack to use a
single mutex for all objects.

#define _GLIBCXX_DEBUG 1
#include <vector>

int main()
{
  std::vector<int> v{1,2,3};
  auto i = v.begin();
  return *i++;
}