diff --git a/test/libc/calls/open_test.c b/test/libc/calls/open_test.c
index 844d88bda..230ef10b2 100644
--- a/test/libc/calls/open_test.c
+++ b/test/libc/calls/open_test.c
@@ -326,120 +326,6 @@ TEST(open, lotsOfFds) {
   }
 }
 
-static int64_t GetInode(const char *path) {
-  struct stat st;
-  ASSERT_SYS(0, 0, stat(path, &st));
-  return st.st_ino;
-}
-
-TEST(open, drive) {
-  if (!IsWindows())
-    return;
-  ASSERT_NE(GetInode("/"), GetInode("."));
-  ASSERT_EQ(GetInode("/"), GetInode("/c"));  // sorry you have to run on c:/
-  ASSERT_EQ(GetInode("/"), GetInode("/c/"));
-  ASSERT_SYS(0, 3, open("/", O_RDONLY));
-  ASSERT_SYS(0, 0, close(3));
-}
-
-TEST(open, readOnlyCreatMode) {
-  char buf[8];
-  struct stat st;
-  ASSERT_SYS(0, 3, open("x", O_RDWR | O_CREAT | O_TRUNC, 0500));
-  ASSERT_SYS(0, 2, pwrite(3, "MZ", 2, 0));
-  ASSERT_SYS(0, 2, pread(3, buf, 8, 0));
-  ASSERT_SYS(0, 0, close(3));
-  ASSERT_SYS(0, 0, stat("x", &st));
-  ASSERT_EQ(0100500, st.st_mode);
-  if (getuid()) {
-    ASSERT_SYS(EACCES, -1, open("x", O_RDWR));
-    ASSERT_SYS(EACCES, -1, open("x", O_RDWR | O_CREAT, 0666));
-  } else {
-    // root is invulnerable to eacces
-    ASSERT_SYS(0, 3, open("x", O_RDWR));
-    ASSERT_SYS(0, 0, close(3));
-    ASSERT_SYS(0, 3, open("x", O_RDWR | O_CREAT, 0666));
-    ASSERT_SYS(0, 0, close(3));
-    SPAWN(fork);
-    setuid(1000);
-    setgid(1000);
-    ASSERT_SYS(EACCES, -1, open("x", O_RDWR));
-    ASSERT_SYS(EACCES, -1, open("x", O_RDWR | O_CREAT, 0666));
-    EXITS(0);
-  }
-}
-
-TEST(open, parentSymlink) {
-  struct stat st;
-  ASSERT_SYS(0, 0, mkdir("parent", 0755));
-  // create directory symlink
-  ASSERT_SYS(0, 0, symlink("parent", "parent-link"));
-  // test the symlink we just made is a symlink
-  ASSERT_SYS(0, 0, lstat("parent-link", &st));
-  ASSERT_TRUE(S_ISLNK(st.st_mode));
-  // create regular file when parent component is symlink dir
-  ASSERT_SYS(0, 0, touch("parent-link/regular", 0644));
-  // test stat works
-  ASSERT_SYS(0, 0, stat("parent-link/regular", &st));
-  ASSERT_TRUE(S_ISREG(st.st_mode));
-  // test open works
-  ASSERT_SYS(0, 3, open("parent-link/regular", O_RDONLY));
-  ASSERT_SYS(0, 0, fstat(3, &st));
-  ASSERT_TRUE(S_ISREG(st.st_mode));
-  ASSERT_SYS(0, 0, close(3));
-  // test O_NOFOLLOW doesn't apply to parent components
-  ASSERT_SYS(0, 3, open("parent-link/regular", O_RDONLY | O_NOFOLLOW));
-  ASSERT_SYS(0, 0, fstat(3, &st));
-  ASSERT_TRUE(S_ISREG(st.st_mode));
-  ASSERT_SYS(0, 0, close(3));
-  // create regular symlink
-  ASSERT_SYS(0, 0, symlink("regular", "parent-link/regular-link"));
-  // test stat works
-  ASSERT_SYS(0, 0, stat("parent-link/regular-link", &st));
-  ASSERT_TRUE(S_ISREG(st.st_mode));
-  ASSERT_SYS(0, 0, lstat("parent-link/regular-link", &st));
-  ASSERT_TRUE(S_ISLNK(st.st_mode));
-  // test open works
-  ASSERT_SYS(0, 3, open("parent-link/regular-link", O_RDONLY));
-  ASSERT_SYS(0, 0, fstat(3, &st));
-  ASSERT_TRUE(S_ISREG(st.st_mode));
-  ASSERT_SYS(0, 0, close(3));
-  // test O_NOFOLLOW applies to last component
-  ASSERT_SYS(ELOOP, -1,
-             open("parent-link/regular-link", O_RDONLY | O_NOFOLLOW));
-}
-
-TEST(open, readonlyCreateMode_dontChangeStatusIfExists) {
-  char buf[8];
-  struct stat st;
-  ASSERT_SYS(0, 3, creat("wut", 0700));
-  ASSERT_SYS(0, 2, pwrite(3, "MZ", 2, 0));
-  ASSERT_SYS(0, 0, close(3));
-  // since the file already exists, unix doesn't change read-only
-  ASSERT_SYS(0, 3, open("wut", O_CREAT | O_TRUNC | O_RDWR, 0500));
-  ASSERT_SYS(0, 0, pread(3, buf, 8, 0));
-  ASSERT_SYS(0, 0, fstat(3, &st));
-  ASSERT_EQ(0100600, st.st_mode & 0700666);
-  ASSERT_SYS(0, 0, close(3));
-}
-
-TEST(open, creatRdonly) {
-  char buf[8];
-  ASSERT_SYS(EINVAL, -1, open("foo", O_CREAT | O_TRUNC | O_RDONLY, 0700));
-  ASSERT_SYS(0, 3, open("foo", O_CREAT | O_RDONLY, 0700));
-  ASSERT_SYS(EBADF, -1, pwrite(3, "MZ", 2, 0));
-  ASSERT_SYS(0, 0, pread(3, buf, 8, 0));
-  ASSERT_SYS(0, 0, close(3));
-}
-
-TEST(open, sequentialRandom_EINVAL) {
-  if (!IsWindows())
-    return;
-  ASSERT_SYS(
-      EINVAL, -1,
-      open("foo", O_CREAT | O_TRUNC | O_RDWR | O_SEQUENTIAL | O_RANDOM, 0700));
-}
-
 // "If O_CREAT is set and the file did not previously exist, upon
 //  successful completion, open() shall mark for update the last data
 //  access, last data modification, and last file status change
@@ -485,33 +371,3 @@ TEST(open, trunc_touchesMtimCtim) {
   EXPECT_EQ(1, timespec_cmp(st.st_mtim, birth));
   ASSERT_SYS(0, 0, close(3));
 }
-
-TEST(open, mereOpen_doesntTouch) {
-  struct stat st;
-  struct timespec birth;
-  ASSERT_SYS(0, 0, touch("regular", 0755));
-  ASSERT_SYS(0, 0, stat("regular", &st));
-  birth = st.st_ctim;
-  sleep(2);
-  ASSERT_SYS(0, 3, open("regular", O_RDWR));
-  ASSERT_SYS(0, 0, close(3));
-  ASSERT_SYS(0, 0, stat("regular", &st));
-  EXPECT_EQ(0, timespec_cmp(st.st_ctim, birth));
-#if 0  // todo: why flake on rhel7?
-  EXPECT_EQ(0, timespec_cmp(st.st_mtim, birth));
-  EXPECT_EQ(0, timespec_cmp(st.st_atim, birth));
-#endif
-}
-
-TEST(open, canTruncateExistingFile) {
-  struct stat st;
-  ASSERT_SYS(0, 0, xbarf("foo", "hello", -1));
-  ASSERT_SYS(0, 0, stat("foo", &st));
-  ASSERT_EQ(5, st.st_size);
-  ASSERT_SYS(0, 3, open("foo", O_RDWR | O_TRUNC));
-  ASSERT_SYS(0, 0, fstat(3, &st));
-  ASSERT_EQ(0, st.st_size);
-  ASSERT_SYS(0, 0, close(3));
-  ASSERT_SYS(0, 0, stat("foo", &st));
-  ASSERT_EQ(0, st.st_size);
-}
diff --git a/third_party/libcxx/BUILD.mk b/third_party/libcxx/BUILD.mk
index 820f75a80..953c37f8d 100644
--- a/third_party/libcxx/BUILD.mk
+++ b/third_party/libcxx/BUILD.mk
@@ -1064,6 +1064,9 @@ third_party/libcxx/ios.instantiations.cpp \
 third_party/libcxx/iostream.cpp \
 third_party/libcxx/legacy_pointer_safety.cpp \
 third_party/libcxx/locale.cpp \
+third_party/libcxx/locale2.cpp \
+third_party/libcxx/locale3.cpp \
+third_party/libcxx/locale4.cpp \
 third_party/libcxx/memory.cpp \
 third_party/libcxx/memory_resource.cpp \
 third_party/libcxx/mutex.cpp \
diff --git a/third_party/libcxx/locale.cpp b/third_party/libcxx/locale.cpp
index 490deccf5..ea8e89f7d 100644
--- a/third_party/libcxx/locale.cpp
+++ b/third_party/libcxx/locale.cpp
@@ -5643,75 +5643,6 @@ void moneypunct_byname<wchar_t, true>::init(const char* nm) {
 }
 #endif // _LIBCPP_HAS_NO_WIDE_CHARACTERS
 
-void __do_nothing(void*) {}
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<wchar_t>;)
-
-template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<wchar_t>;)
-
-template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, false>;
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, true>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, false>;)
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, true>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, false>;
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, true>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, false>;)
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, true>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<char>;
-_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<wchar_t>;)
-
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char, char, mbstate_t>;
-_LIBCPP_IF_WIDE_CHARACTERS(
-    template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<wchar_t, char, mbstate_t>;)
-template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-    codecvt_byname<char16_t, char, mbstate_t>;
-template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
-    codecvt_byname<char32_t, char, mbstate_t>;
-#ifndef _LIBCPP_HAS_NO_CHAR8_T
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char8_t, mbstate_t>;
-template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char8_t, mbstate_t>;
-#endif
-
 _LIBCPP_END_NAMESPACE_STD
 
 _LIBCPP_POP_MACROS
diff --git a/third_party/libcxx/locale2.cpp b/third_party/libcxx/locale2.cpp
new file mode 100644
index 000000000..0e9778f1d
--- /dev/null
+++ b/third_party/libcxx/locale2.cpp
@@ -0,0 +1,69 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__utility/no_destroy.h>
+#include <algorithm>
+#include <clocale>
+#include <codecvt>
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <locale>
+#include <new>
+#include <string>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <vector>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <cwctype>
+#endif
+
+#if defined(_AIX)
+#  include <sys/localedef.h> // for __lc_ctype_ptr
+#endif
+
+#if defined(_LIBCPP_MSVCRT)
+#  define _CTYPE_DISABLE_MACROS
+#endif
+
+#if !defined(_LIBCPP_MSVCRT) && !defined(__MINGW32__) && !defined(__BIONIC__) && !defined(__NuttX__)
+#  include <langinfo.h>
+#endif
+
+#include "atomic_support.h"
+#include "sso_allocator.h"
+
+// On Linux, wint_t and wchar_t have different signed-ness, and this causes
+// lots of noise in the build log, but no bugs that I know of.
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wsign-conversion")
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+void __do_nothing(void*) {}
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS collate<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_get<wchar_t>;)
+
+template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_get<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS num_put<wchar_t>;)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
diff --git a/third_party/libcxx/locale3.cpp b/third_party/libcxx/locale3.cpp
new file mode 100644
index 000000000..c185d1e44
--- /dev/null
+++ b/third_party/libcxx/locale3.cpp
@@ -0,0 +1,95 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__utility/no_destroy.h>
+#include <algorithm>
+#include <clocale>
+#include <codecvt>
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <locale>
+#include <new>
+#include <string>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <vector>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <cwctype>
+#endif
+
+#if defined(_AIX)
+#  include <sys/localedef.h> // for __lc_ctype_ptr
+#endif
+
+#if defined(_LIBCPP_MSVCRT)
+#  define _CTYPE_DISABLE_MACROS
+#endif
+
+#if !defined(_LIBCPP_MSVCRT) && !defined(__MINGW32__) && !defined(__BIONIC__) && !defined(__NuttX__)
+#  include <langinfo.h>
+#endif
+
+#include "atomic_support.h"
+#include "sso_allocator.h"
+
+// On Linux, wint_t and wchar_t have different signed-ness, and this causes
+// lots of noise in the build log, but no bugs that I know of.
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wsign-conversion")
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, false>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<char, true>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, false>;)
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct<wchar_t, true>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, false>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<char, true>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, false>;)
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS moneypunct_byname<wchar_t, true>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_get<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_get<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS money_put<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __money_put<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS messages_byname<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char, char, mbstate_t>;
+_LIBCPP_IF_WIDE_CHARACTERS(
+    template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<wchar_t, char, mbstate_t>;)
+template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+    codecvt_byname<char16_t, char, mbstate_t>;
+template class _LIBCPP_DEPRECATED_IN_CXX20 _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS
+    codecvt_byname<char32_t, char, mbstate_t>;
+#ifndef _LIBCPP_HAS_NO_CHAR8_T
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char16_t, char8_t, mbstate_t>;
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS codecvt_byname<char32_t, char8_t, mbstate_t>;
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
diff --git a/third_party/libcxx/locale4.cpp b/third_party/libcxx/locale4.cpp
new file mode 100644
index 000000000..3e6d757e2
--- /dev/null
+++ b/third_party/libcxx/locale4.cpp
@@ -0,0 +1,70 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <__utility/no_destroy.h>
+#include <algorithm>
+#include <clocale>
+#include <codecvt>
+#include <cstddef>
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <locale>
+#include <new>
+#include <string>
+#include <type_traits>
+#include <typeinfo>
+#include <utility>
+#include <vector>
+
+#ifndef _LIBCPP_HAS_NO_WIDE_CHARACTERS
+#  include <cwctype>
+#endif
+
+#if defined(_AIX)
+#  include <sys/localedef.h> // for __lc_ctype_ptr
+#endif
+
+#if defined(_LIBCPP_MSVCRT)
+#  define _CTYPE_DISABLE_MACROS
+#endif
+
+#if !defined(_LIBCPP_MSVCRT) && !defined(__MINGW32__) && !defined(__BIONIC__) && !defined(__NuttX__)
+#  include <langinfo.h>
+#endif
+
+#include "atomic_support.h"
+#include "sso_allocator.h"
+
+// On Linux, wint_t and wchar_t have different signed-ness, and this causes
+// lots of noise in the build log, but no bugs that I know of.
+_LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wsign-conversion")
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template struct _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS __num_put<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_get_byname<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put<wchar_t>;)
+
+template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<char>;
+_LIBCPP_IF_WIDE_CHARACTERS(template class _LIBCPP_CLASS_TEMPLATE_INSTANTIATION_VIS time_put_byname<wchar_t>;)
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
diff --git a/tool/cosmocc/package.sh b/tool/cosmocc/package.sh
index 2ba718252..988b6dc79 100755
--- a/tool/cosmocc/package.sh
+++ b/tool/cosmocc/package.sh
@@ -19,12 +19,13 @@ OUTDIR=${1:-cosmocc}
 APELINK=o/$(mode)/tool/build/apelink
 AMD64=${2:-x86_64}
 ARM64=${3:-aarch64}
+NPROC=$(($(nproc)/2))
 GCCVER=14.1.0
 
-make -j64 m= \
+make -j$NPROC m= \
   $APELINK
 
-make -j64 m=$AMD64 \
+make -j$NPROC m=$AMD64 \
   o/cosmocc.h.txt \
   o/$AMD64/ape/ape.lds \
   o/$AMD64/libc/crt/crt.o \
@@ -61,7 +62,7 @@ make -j64 m=$AMD64 \
   o/$AMD64/third_party/make/make.dbg \
   o/$AMD64/third_party/ctags/ctags.dbg
 
-make -j64 m=$AMD64-tiny \
+make -j$NPROC m=$AMD64-tiny \
   o/cosmocc.h.txt \
   o/$AMD64-tiny/ape/ape.lds \
   o/$AMD64-tiny/libc/crt/crt.o \
@@ -73,7 +74,7 @@ make -j64 m=$AMD64-tiny \
   o/$AMD64-tiny/cosmopolitan.a \
   o/$AMD64-tiny/third_party/libcxx/libcxx.a \
 
-make -j64 m=$AMD64-dbg \
+make -j$NPROC m=$AMD64-dbg \
   o/cosmocc.h.txt \
   o/$AMD64-dbg/ape/ape.lds \
   o/$AMD64-dbg/libc/crt/crt.o \
@@ -85,7 +86,7 @@ make -j64 m=$AMD64-dbg \
   o/$AMD64-dbg/cosmopolitan.a \
   o/$AMD64-dbg/third_party/libcxx/libcxx.a \
 
-make CONFIG_TARGET_ARCH= -j64 m=$AMD64-optlinux \
+make CONFIG_TARGET_ARCH= -j$NPROC m=$AMD64-optlinux \
   o/cosmocc.h.txt \
   o/$AMD64-optlinux/ape/ape.lds \
   o/$AMD64-optlinux/libc/crt/crt.o \
@@ -97,7 +98,7 @@ make CONFIG_TARGET_ARCH= -j64 m=$AMD64-optlinux \
   o/$AMD64-optlinux/cosmopolitan.a \
   o/$AMD64-optlinux/third_party/libcxx/libcxx.a \
 
-make -j64 m=$ARM64 \
+make -j$NPROC m=$ARM64 \
   o/$ARM64/ape/ape.elf \
   o/$ARM64/ape/aarch64.lds \
   o/$ARM64/libc/crt/crt.o \
@@ -131,7 +132,7 @@ make -j64 m=$ARM64 \
   o/$ARM64/third_party/make/make.dbg \
   o/$ARM64/third_party/ctags/ctags.dbg
 
-make -j64 m=$ARM64-tiny \
+make -j$NPROC m=$ARM64-tiny \
   o/$ARM64-tiny/ape/ape.elf \
   o/$ARM64-tiny/ape/aarch64.lds \
   o/$ARM64-tiny/libc/crt/crt.o \
@@ -140,7 +141,7 @@ make -j64 m=$ARM64-tiny \
   o/$ARM64-tiny/cosmopolitan.a \
   o/$ARM64-tiny/third_party/libcxx/libcxx.a \
 
-make -j64 m=$ARM64-dbg \
+make -j$NPROC m=$ARM64-dbg \
   o/$ARM64-dbg/ape/ape.elf \
   o/$ARM64-dbg/ape/aarch64.lds \
   o/$ARM64-dbg/libc/crt/crt.o \
@@ -149,7 +150,7 @@ make -j64 m=$ARM64-dbg \
   o/$ARM64-dbg/cosmopolitan.a \
   o/$ARM64-dbg/third_party/libcxx/libcxx.a \
 
-make -j64 m=$ARM64-optlinux \
+make -j$NPROC m=$ARM64-optlinux \
   o/$ARM64-optlinux/ape/ape.elf \
   o/$ARM64-optlinux/ape/aarch64.lds \
   o/$ARM64-optlinux/libc/crt/crt.o \