On Sat, 12 Apr 2025, Jeremy Drake via Cygwin-apps wrote: > Maybe setting -DCMAKE_CXX_STANDARD=20 would work around this? It would at > least take a different path in that if/elif block in basic_string.
It does indeed work around this, and builds a functional dylib llvm/clang on Cygwin. > But I > think we need to figure out why the extern template isn't working > regardless. I opened https://github.com/msys2/MSYS2-packages/issues/5329 . If this reproduces with a mingw-w64 libstdc++ built with the gcc4 abi option, I would feel more comfortable opening an issue with llvm/llvm-project than I would for a target that already requires a bunch of non-upstreamed hacks to work at all.
