diff --git a/src/libs/libunwind.zig b/src/libs/libunwind.zig
index 46c4b0332aad75d110ab172ccc3209a8257c66b4..fb3b20684bc90117d10bebd2082ac97367124be1 100644
--- a/src/libs/libunwind.zig
+++ b/src/libs/libunwind.zig
@@ -124,6 +124,9 @@ pub fn buildStaticLib(comp: *Compilation, prog_node: std.Progress.Node) BuildErr
         if (!comp.config.any_non_single_threaded) {
             try cflags.append("-D_LIBUNWIND_HAS_NO_THREADS");
         }
+        if (target.os.tag == .haiku) {
+            try cflags.append("-D_LIBUNWIND_USE_HAIKU_BSD_LIB");
+        }
         if (target.cpu.arch.isArm() and target.abi.float() == .hard) {
             try cflags.append("-DCOMPILER_RT_ARMHF_TARGET");
         }