diff --git a/lib/std/Thread.zig b/lib/std/Thread.zig
index ac38e5b4c6..1fe8ca89d2 100644
--- a/lib/std/Thread.zig
+++ b/lib/std/Thread.zig
@@ -558,7 +558,7 @@ const PosixThreadImpl = struct {
             .openbsd => {
                 var count: c_int = undefined;
                 var count_size: usize = @sizeOf(c_int);
-                const mib = [_]c_int{ os.CTL.HW, os.HW_NCPUONLINE };
+                const mib = [_]c_int{ os.CTL.HW, os.system.HW_NCPUONLINE };
                 os.sysctl(&mib, &count, &count_size, null, 0) catch |err| switch (err) {
                     error.NameTooLong, error.UnknownName => unreachable,
                     else => |e| return e,
diff --git a/lib/std/c/darwin.zig b/lib/std/c/darwin.zig
index a3c57f5204..8bb30efab3 100644
--- a/lib/std/c/darwin.zig
+++ b/lib/std/c/darwin.zig
@@ -1436,9 +1436,9 @@ pub const SS_ONSTACK = 1;
 pub const SS_DISABLE = 4;
 
 pub const stack_t = extern struct {
-    ss_sp: [*]u8,
-    ss_size: isize,
-    ss_flags: i32,
+    sp: [*]u8,
+    size: isize,
+    flags: i32,
 };
 
 pub const S = struct {
diff --git a/lib/std/c/dragonfly.zig b/lib/std/c/dragonfly.zig
index 82e50a5002..35bbeac6a3 100644
--- a/lib/std/c/dragonfly.zig
+++ b/lib/std/c/dragonfly.zig
@@ -547,9 +547,9 @@ pub const NOTE_FFCOPY = 3221225472;
 pub const NOTE_PCTRLMASK = 4026531840;
 
 pub const stack_t = extern struct {
-    ss_sp: [*]u8,
-    ss_size: isize,
-    ss_flags: i32,
+    sp: [*]u8,
+    size: isize,
+    flags: i32,
 };
 
 pub const S = struct {
diff --git a/lib/std/c/haiku.zig b/lib/std/c/haiku.zig
index 38875d29f9..1ad51cfadd 100644
--- a/lib/std/c/haiku.zig
+++ b/lib/std/c/haiku.zig
@@ -1006,9 +1006,9 @@ pub const SS_ONSTACK = 1;
 pub const SS_DISABLE = 4;
 
 pub const stack_t = extern struct {
-    ss_sp: [*]u8,
-    ss_size: isize,
-    ss_flags: i32,
+    sp: [*]u8,
+    size: isize,
+    flags: i32,
 };
 
 pub const S = struct {
diff --git a/lib/std/c/netbsd.zig b/lib/std/c/netbsd.zig
index d85c8c41b7..e492ce60fe 100644
--- a/lib/std/c/netbsd.zig
+++ b/lib/std/c/netbsd.zig
@@ -1039,9 +1039,11 @@ pub const mcontext_t = extern struct {
     fpregs: [512]u8 align(8),
 };
 
-pub const REG_RBP = 12;
-pub const REG_RIP = 21;
-pub const REG_RSP = 24;
+pub const REG = struct {
+    pub const RBP = 12;
+    pub const RIP = 21;
+    pub const RSP = 24;
+};
 
 pub const ucontext_t = extern struct {
     flags: u32,
@@ -1206,9 +1208,9 @@ pub const SS_ONSTACK = 1;
 pub const SS_DISABLE = 4;
 
 pub const stack_t = extern struct {
-    ss_sp: [*]u8,
-    ss_size: isize,
-    ss_flags: i32,
+    sp: [*]u8,
+    size: isize,
+    flags: i32,
 };
 
 pub const S = struct {
diff --git a/lib/std/c/openbsd.zig b/lib/std/c/openbsd.zig
index fb8738d737..b3919d4724 100644
--- a/lib/std/c/openbsd.zig
+++ b/lib/std/c/openbsd.zig
@@ -1007,9 +1007,9 @@ pub const SS_ONSTACK = 0x0001;
 pub const SS_DISABLE = 0x0004;
 
 pub const stack_t = extern struct {
-    ss_sp: [*]u8,
-    ss_size: usize,
-    ss_flags: c_int,
+    sp: [*]u8,
+    size: usize,
+    flags: c_int,
 };
 
 pub const S = struct {
diff --git a/lib/std/os/linux.zig b/lib/std/os/linux.zig
index c4309e288d..12a8f3906e 100644
--- a/lib/std/os/linux.zig
+++ b/lib/std/os/linux.zig
@@ -3080,15 +3080,15 @@ pub const SS_AUTODISARM = 1 << 31;
 pub const stack_t = if (is_mips)
     // IRIX compatible stack_t
     extern struct {
-        ss_sp: [*]u8,
-        ss_size: usize,
-        ss_flags: i32,
+        sp: [*]u8,
+        size: usize,
+        flags: i32,
     }
 else
     extern struct {
-        ss_sp: [*]u8,
-        ss_flags: i32,
-        ss_size: usize,
+        sp: [*]u8,
+        flags: i32,
+        size: usize,
     };
 
 pub const sigval = extern union {
diff --git a/lib/std/os/test.zig b/lib/std/os/test.zig
index 21a02a8c8f..3a0187f735 100644
--- a/lib/std/os/test.zig
+++ b/lib/std/os/test.zig
@@ -394,8 +394,8 @@ test "sigaltstack" {
     var st: os.stack_t = undefined;
     try os.sigaltstack(null, &st);
     // Setting a stack size less than MINSIGSTKSZ returns ENOMEM
-    st.ss_flags = 0;
-    st.ss_size = 1;
+    st.flags = 0;
+    st.size = 1;
     try testing.expectError(error.SizeTooSmall, os.sigaltstack(&st, null));
 }