[Bug libstdc++/86138] C++17: getline(istream, string) crashes on Cygwin because incompatible C++14 function is called

[franke at computer dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86138

--- Comment #12 from Christian Franke <franke at computer dot org> ---
(In reply to Jonathan Wakely from comment #7)
> OK, so then this is the whack Windows linker model, where every DLL has its
> own address space, and probably the same as PR 81522.

Yes. Likely also affects MinGW libstdc++6.dll.

> Does Cygwin default to _GLIBCXX_USE_CXX11_ABI=0?

Yes.

Possible fix for Cygwin:
- Rebuild cygstdc++6.dll with C++17 enabled
- Disable/Remove '__cplusplus <= 201402L' condition around the extern template
block in this case.