https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97729
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It could be a difference in the linker. I'm using the mingw cross-binutils that
comes with Fedora:
$ /usr/bin/x86_64-w64-mingw32-ld --version
GNU ld version 2.32-%{release}
Copyright (C) 2019 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License version 3 or (at your option) a later version.
This program has absolutely no warranty.
The exception_ptr symbols should get suppressed with:
--- a/libstdc++-v3/src/c++11/future.cc
+++ b/libstdc++-v3/src/c++11/future.cc
@@ -22,6 +22,9 @@
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
+// Prevent multiple definitions of exception_ptr inline members (PR 97729)
+#define _GLIBCXX_EH_PTR_COMPAT
+
#include <future>
#include <bits/functexcept.h>
