src/libunwind.zig: Fix symbol visibility macro define

The define was changed in commit 729899f7b6bf6aff65988d895d7a639391a67608
in upstream llvm.
d5ac3be608Luis Cáceres committed on 4/12/2025, 8:27:28 PM· committed by Alex Rønne Petersenparenta7122b7
1 file changedLine totals unavailable