diff --git a/lib/std/c.zig b/lib/std/c.zig
index ced6e7f3b7bd41b8f933aa2ea1b56548669d87b8..bf724f5bff157d82f1897d7a850adf66a9309488 100644
--- a/lib/std/c.zig
+++ b/lib/std/c.zig
@@ -4904,7 +4904,7 @@ pub const sigset_t = switch (native_os) {
 pub const sigval = switch (native_os) {
     .linux => linux.sigval,
     // https://github.com/SerenityOS/serenity/blob/ec492a1a0819e6239ea44156825c4ee7234ca3db/Kernel/API/POSIX/signal.h#L22-L25
-    .openbsd, .dragonfly, .freebsd, .serenity => extern union {
+    .openbsd, .dragonfly, .freebsd, .haiku, .serenity => extern union {
         int: c_int,
         ptr: ?*anyopaque,
     },