Stablizing ABIs on Windows

[unlvsur unlvsur]

Currently GCC supports win32, posix and mcf thread model on windows and they are not binary compatible, causing a lot of issues.

I suggest to rename win32 and mcf's libstdc++ dll to

Win32: libstdc++-6_win32.dll
mcf: libstdc++-6_mcf.dll

Since majority of windows mingw distributions ship posix thread model
libstdc++-6.dll should be remained as the name for posix thread model
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://gcc.gnu.org/pipermail/libstdc++/attachments/20240614/c28ff31a/attachment.htm>