[llvm-branch-commits] [libcxx] [lldb] release/21.x: [libc++] Ensure that we restore invariants in basic_filebuf::overflow (#147389) (PR #155712)

[Tulio Magno Quites Machado Filho via llvm-branch-commits]

tuliom wrote:

@philnik777 This PR now has the commits from #149390 and #154962 too.

https://github.com/llvm/llvm-project/pull/155712