diff --git a/lib/std/os/bits.zig b/lib/std/os/bits.zig
index 5d1de28badff951dccdaf405bf8beefaae609abb..5c396091825f358816ad0a0c99e96dd5a94c455b 100644
--- a/lib/std/os/bits.zig
+++ b/lib/std/os/bits.zig
@@ -25,32 +25,3 @@ pub usingnamespace switch (std.Target.current.os.tag) {
 };
 
 pub usingnamespace if (@hasDecl(root, "os") and @hasDecl(root.os, "bits")) root.os.bits else struct {};
-
-pub const iovec = extern struct {
-    iov_base: [*]u8,
-    iov_len: usize,
-};
-
-pub const iovec_const = extern struct {
-    iov_base: [*]const u8,
-    iov_len: usize,
-};
-
-// syslog
-
-/// system is unusable
-pub const LOG_EMERG = 0;
-/// action must be taken immediately
-pub const LOG_ALERT = 1;
-/// critical conditions
-pub const LOG_CRIT = 2;
-/// error conditions
-pub const LOG_ERR = 3;
-/// warning conditions
-pub const LOG_WARNING = 4;
-/// normal but significant condition
-pub const LOG_NOTICE = 5;
-/// informational
-pub const LOG_INFO = 6;
-/// debug-level messages
-pub const LOG_DEBUG = 7;
diff --git a/lib/std/os/bits/darwin.zig b/lib/std/os/bits/darwin.zig
index be77722c05780e21873c830689835bd7e6a0f0d3..91705c0d2e44561d81e9049b1639ec41ca4def7f 100644
--- a/lib/std/os/bits/darwin.zig
+++ b/lib/std/os/bits/darwin.zig
@@ -7,6 +7,8 @@ const std = @import("../../std.zig");
 const assert = std.debug.assert;
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 // See: https://opensource.apple.com/source/xnu/xnu-6153.141.1/bsd/sys/_types.h.auto.html
 // TODO: audit mode_t/pid_t, should likely be u16/i32
 pub const fd_t = c_int;
diff --git a/lib/std/os/bits/dragonfly.zig b/lib/std/os/bits/dragonfly.zig
index 9f6d3088baf5a531cbb752ebfcd575f91ee0d2d7..573721749cd5f167ca81efe612b207afad704366 100644
--- a/lib/std/os/bits/dragonfly.zig
+++ b/lib/std/os/bits/dragonfly.zig
@@ -6,6 +6,8 @@
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 pub fn S_ISCHR(m: u32) bool {
     return m & S_IFMT == S_IFCHR;
 }
diff --git a/lib/std/os/bits/freebsd.zig b/lib/std/os/bits/freebsd.zig
index 6d227a168a7ed95f42018acbc86d38a7505b4ece..1805941993943c6dbef53fe710ede0f55dcdf472 100644
--- a/lib/std/os/bits/freebsd.zig
+++ b/lib/std/os/bits/freebsd.zig
@@ -7,6 +7,8 @@ const std = @import("../../std.zig");
 const builtin = @import("builtin");
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 pub const blksize_t = i32;
 pub const blkcnt_t = i64;
 pub const clockid_t = i32;
diff --git a/lib/std/os/bits/haiku.zig b/lib/std/os/bits/haiku.zig
index cb31166608e9e4bc6d9b7fa367f03a0f181d5b90..b3ea4aa0e2236e101e2eab99522edae9e6449342 100644
--- a/lib/std/os/bits/haiku.zig
+++ b/lib/std/os/bits/haiku.zig
@@ -6,6 +6,8 @@
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 pub const fd_t = c_int;
 pub const pid_t = c_int;
 pub const uid_t = u32;
diff --git a/lib/std/os/bits/linux.zig b/lib/std/os/bits/linux.zig
index 81bdfa6608cd6cb001608a4af58b2ce3aef6f41b..28683d47a96f836a54d6354a80e756eb19ca1c77 100644
--- a/lib/std/os/bits/linux.zig
+++ b/lib/std/os/bits/linux.zig
@@ -6,7 +6,7 @@
 const std = @import("../../std.zig");
 const maxInt = std.math.maxInt;
 const arch = @import("builtin").target.cpu.arch;
-usingnamespace @import("../bits.zig");
+pub usingnamespace @import("posix.zig");
 
 pub usingnamespace switch (arch) {
     .mips, .mipsel => @import("linux/errno-mips.zig"),
diff --git a/lib/std/os/bits/netbsd.zig b/lib/std/os/bits/netbsd.zig
index d0240709e3dd110aa15efdd9257639d73247f0bc..f3ece9349334ea529a953b9785e41c66e01151ab 100644
--- a/lib/std/os/bits/netbsd.zig
+++ b/lib/std/os/bits/netbsd.zig
@@ -7,6 +7,8 @@ const std = @import("../../std.zig");
 const builtin = std.builtin;
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 pub const blkcnt_t = i64;
 pub const blksize_t = i32;
 pub const clock_t = u32;
diff --git a/lib/std/os/bits/openbsd.zig b/lib/std/os/bits/openbsd.zig
index 3b9f8ccd4aaf40f5052af1f0f43835c0d4a352c9..233ebcbd684b78f7cb9f359753217b56f85d2ae5 100644
--- a/lib/std/os/bits/openbsd.zig
+++ b/lib/std/os/bits/openbsd.zig
@@ -7,6 +7,8 @@ const std = @import("../../std.zig");
 const builtin = std.builtin;
 const maxInt = std.math.maxInt;
 
+pub usingnamespace @import("posix.zig");
+
 pub const blkcnt_t = i64;
 pub const blksize_t = i32;
 pub const clock_t = i64;
diff --git a/lib/std/os/bits/posix.zig b/lib/std/os/bits/posix.zig
new file mode 100644
index 0000000000000000000000000000000000000000..0f015cd57356c62a2943fd944e631837c13c5f1d
--- /dev/null
+++ b/lib/std/os/bits/posix.zig
@@ -0,0 +1,34 @@
+// SPDX-License-Identifier: MIT
+// Copyright (c) 2015-2021 Zig Contributors
+// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
+// The MIT license requires this copyright notice to be included in all copies
+// and substantial portions of the software.
+
+pub const iovec = extern struct {
+    iov_base: [*]u8,
+    iov_len: usize,
+};
+
+pub const iovec_const = extern struct {
+    iov_base: [*]const u8,
+    iov_len: usize,
+};
+
+// syslog
+
+/// system is unusable
+pub const LOG_EMERG = 0;
+/// action must be taken immediately
+pub const LOG_ALERT = 1;
+/// critical conditions
+pub const LOG_CRIT = 2;
+/// error conditions
+pub const LOG_ERR = 3;
+/// warning conditions
+pub const LOG_WARNING = 4;
+/// normal but significant condition
+pub const LOG_NOTICE = 5;
+/// informational
+pub const LOG_INFO = 6;
+/// debug-level messages
+pub const LOG_DEBUG = 7;
diff --git a/lib/std/os/bits/wasi.zig b/lib/std/os/bits/wasi.zig
index 8b2f5c3351a552c4d5a21a31a7f27bf7fc872b72..5cb133403791b670edc9d3a5f9c2e94404e3f4aa 100644
--- a/lib/std/os/bits/wasi.zig
+++ b/lib/std/os/bits/wasi.zig
@@ -4,6 +4,10 @@
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
 // Convenience types and consts used by std.os module
+const posix = @import("posix.zig");
+pub const iovec = posix.iovec;
+pub const iovec_const = posix.iovec_const;
+
 pub const STDIN_FILENO = 0;
 pub const STDOUT_FILENO = 1;
 pub const STDERR_FILENO = 2;
diff --git a/lib/std/os/bits/windows.zig b/lib/std/os/bits/windows.zig
index c5b101296bffe199184155b5fd3fc06d5bedadf9..05c50ffe475de3a455b9b98d108c1bdf09e154be 100644
--- a/lib/std/os/bits/windows.zig
+++ b/lib/std/os/bits/windows.zig
@@ -8,6 +8,11 @@
 usingnamespace @import("../windows/bits.zig");
 const ws2_32 = @import("../windows/ws2_32.zig");
 
+// TODO: Stop using os.iovec in std.fs et al on Windows in the future
+const posix = @import("posix.zig");
+pub const iovec = posix.iovec;
+pub const iovec_const = posix.iovec_const;
+
 pub const fd_t = HANDLE;
 pub const ino_t = LARGE_INTEGER;
 pub const pid_t = HANDLE;
diff --git a/lib/std/os/linux/arm-eabi.zig b/lib/std/os/linux/arm-eabi.zig
index 0fe74c966520aa7b899b7871250f90e17cd8c503..469b7299d194c3a720ce03acb5c60ca90879ba1a 100644
--- a/lib/std/os/linux/arm-eabi.zig
+++ b/lib/std/os/linux/arm-eabi.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/arm64.zig b/lib/std/os/linux/arm64.zig
index 0e1af984934435aa53fe9d38df41aa3f03b8ce93..4c8306c048d980dafefebc1254eb4742c7c478f3 100644
--- a/lib/std/os/linux/arm64.zig
+++ b/lib/std/os/linux/arm64.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/i386.zig b/lib/std/os/linux/i386.zig
index df58336eb0da87694c789e0c77fcbfb930fef84c..2ec34bac40f2547c481282bc774427afe3f84ac4 100644
--- a/lib/std/os/linux/i386.zig
+++ b/lib/std/os/linux/i386.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/mips.zig b/lib/std/os/linux/mips.zig
index 2ac029cae8283e3673e79390097dce8d0f5d65a3..85157f04f865f39d14068c7c67fc6a88c80f7db7 100644
--- a/lib/std/os/linux/mips.zig
+++ b/lib/std/os/linux/mips.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/powerpc.zig b/lib/std/os/linux/powerpc.zig
index 341eb3f920a775f10791d5b13b4e016fa4b3a58b..611eee1c5f0bd8257d35f0004028379a0b677a53 100644
--- a/lib/std/os/linux/powerpc.zig
+++ b/lib/std/os/linux/powerpc.zig
@@ -4,7 +4,6 @@
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
 
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/powerpc64.zig b/lib/std/os/linux/powerpc64.zig
index 341eb3f920a775f10791d5b13b4e016fa4b3a58b..611eee1c5f0bd8257d35f0004028379a0b677a53 100644
--- a/lib/std/os/linux/powerpc64.zig
+++ b/lib/std/os/linux/powerpc64.zig
@@ -4,7 +4,6 @@
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
 
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/riscv64.zig b/lib/std/os/linux/riscv64.zig
index cab2ecfbafd973a96e9399f2411d9974eb3d9bf0..3e2b15b599c016cb506c94e38836830805451e14 100644
--- a/lib/std/os/linux/riscv64.zig
+++ b/lib/std/os/linux/riscv64.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {
diff --git a/lib/std/os/linux/sparc64.zig b/lib/std/os/linux/sparc64.zig
index cbe5ee3b704658ccc199c762e52d4921e809b13d..f347a0e88e71b4146037d351ca9dd480dd6c62e8 100644
--- a/lib/std/os/linux/sparc64.zig
+++ b/lib/std/os/linux/sparc64.zig
@@ -1,4 +1,3 @@
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall_pipe(fd: *[2]i32) usize {
diff --git a/lib/std/os/linux/thumb.zig b/lib/std/os/linux/thumb.zig
index 955c3420d431d589cf5f04113a9226a17dcb4b05..85f8bfc52b41c7f3dc2c8889767fc0a5d7f106d2 100644
--- a/lib/std/os/linux/thumb.zig
+++ b/lib/std/os/linux/thumb.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 // The syscall interface is identical to the ARM one but we're facing an extra
diff --git a/lib/std/os/linux/x86_64.zig b/lib/std/os/linux/x86_64.zig
index da4206a521354c4bc16247b340dab90ebbdeffd5..5aa32c56c3023da92bb55c876329ca3e237f2188 100644
--- a/lib/std/os/linux/x86_64.zig
+++ b/lib/std/os/linux/x86_64.zig
@@ -3,7 +3,6 @@
 // This file is part of [zig](https://ziglang.org/), which is MIT licensed.
 // The MIT license requires this copyright notice to be included in all copies
 // and substantial portions of the software.
-usingnamespace @import("../bits.zig");
 usingnamespace @import("../bits/linux.zig");
 
 pub fn syscall0(number: SYS) usize {