diff --git a/lib/std/c/darwin.zig b/lib/std/c/darwin.zig
index 573f29150d..b925a15942 100644
--- a/lib/std/c/darwin.zig
+++ b/lib/std/c/darwin.zig
@@ -59,6 +59,7 @@ pub const EXC = enum(exception_type_t) {
     pub const SOFT_SIGNAL = 0x10003;
 
     pub const MASK = packed struct(u32) {
+        _0: u1 = 0,
         BAD_ACCESS: bool = false,
         BAD_INSTRUCTION: bool = false,
         ARITHMETIC: bool = false,
@@ -72,6 +73,7 @@ pub const EXC = enum(exception_type_t) {
         RESOURCE: bool = false,
         GUARD: bool = false,
         CORPSE_NOTIFY: bool = false,
+        _14: u18 = 0,
 
         pub const MACHINE: MASK = @bitCast(@as(u32, 0));