diff --git a/libc/src/dirent/closedir.cpp b/libc/src/dirent/closedir.cpp
--- a/libc/src/dirent/closedir.cpp
+++ b/libc/src/dirent/closedir.cpp
@@ -10,9 +10,9 @@
 
 #include "src/__support/File/dir.h"
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
 #include <dirent.h>
-#include <errno.h>
 
 namespace __llvm_libc {
 
@@ -20,7 +20,7 @@
   auto *d = reinterpret_cast<__llvm_libc::Dir *>(dir);
   int retval = d->close();
   if (retval != 0) {
-    errno = retval;
+    libc_errno = retval;
     return -1;
   }
   return 0;
diff --git a/libc/src/dirent/opendir.cpp b/libc/src/dirent/opendir.cpp
--- a/libc/src/dirent/opendir.cpp
+++ b/libc/src/dirent/opendir.cpp
@@ -10,16 +10,16 @@
 
 #include "src/__support/File/dir.h"
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
 #include <dirent.h>
-#include <errno.h>
 
 namespace __llvm_libc {
 
 LLVM_LIBC_FUNCTION(::DIR *, opendir, (const char *name)) {
   auto dir = Dir::open(name);
   if (!dir) {
-    errno = dir.error();
+    libc_errno = dir.error();
     return nullptr;
   }
   return reinterpret_cast<DIR *>(dir.value());
diff --git a/libc/src/dirent/readdir.cpp b/libc/src/dirent/readdir.cpp
--- a/libc/src/dirent/readdir.cpp
+++ b/libc/src/dirent/readdir.cpp
@@ -10,9 +10,9 @@
 
 #include "src/__support/File/dir.h"
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
 #include <dirent.h>
-#include <errno.h>
 
 namespace __llvm_libc {
 
@@ -20,7 +20,7 @@
   auto *d = reinterpret_cast<__llvm_libc::Dir *>(dir);
   auto dirent_val = d->read();
   if (!dirent_val) {
-    errno = dirent_val.error();
+    libc_errno = dirent_val.error();
     return nullptr;
   }
   return dirent_val;
diff --git a/libc/src/fcntl/linux/CMakeLists.txt b/libc/src/fcntl/linux/CMakeLists.txt
--- a/libc/src/fcntl/linux/CMakeLists.txt
+++ b/libc/src/fcntl/linux/CMakeLists.txt
@@ -5,7 +5,6 @@
   HDRS
     ../creat.h
   DEPENDS
-    libc.include.errno
     libc.include.fcntl
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
@@ -18,7 +17,6 @@
   HDRS
     ../open.h
   DEPENDS
-    libc.include.errno
     libc.include.fcntl
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
@@ -31,7 +29,6 @@
   HDRS
     ../openat.h
   DEPENDS
-    libc.include.errno
     libc.include.fcntl
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
diff --git a/libc/src/fcntl/linux/creat.cpp b/libc/src/fcntl/linux/creat.cpp
--- a/libc/src/fcntl/linux/creat.cpp
+++ b/libc/src/fcntl/linux/creat.cpp
@@ -10,8 +10,8 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
-#include <errno.h>
 #include <fcntl.h>
 #include <sys/syscall.h> // For syscall numbers.
 
@@ -29,7 +29,7 @@
   if (fd > 0)
     return fd;
 
-  errno = -fd;
+  libc_errno = -fd;
   return -1;
 }
 
diff --git a/libc/src/fcntl/linux/open.cpp b/libc/src/fcntl/linux/open.cpp
--- a/libc/src/fcntl/linux/open.cpp
+++ b/libc/src/fcntl/linux/open.cpp
@@ -10,8 +10,8 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
-#include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <sys/syscall.h> // For syscall numbers.
@@ -38,7 +38,7 @@
   if (fd > 0)
     return fd;
 
-  errno = -fd;
+  libc_errno = -fd;
   return -1;
 }
 
diff --git a/libc/src/fcntl/linux/openat.cpp b/libc/src/fcntl/linux/openat.cpp
--- a/libc/src/fcntl/linux/openat.cpp
+++ b/libc/src/fcntl/linux/openat.cpp
@@ -10,8 +10,8 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
-#include <errno.h>
 #include <fcntl.h>
 #include <stdarg.h>
 #include <sys/syscall.h> // For syscall numbers.
@@ -33,7 +33,7 @@
   if (fd > 0)
     return fd;
 
-  errno = -fd;
+  libc_errno = -fd;
   return -1;
 }
 
diff --git a/libc/src/inttypes/CMakeLists.txt b/libc/src/inttypes/CMakeLists.txt
--- a/libc/src/inttypes/CMakeLists.txt
+++ b/libc/src/inttypes/CMakeLists.txt
@@ -6,6 +6,7 @@
     strtoimax.h
   DEPENDS
     libc.src.__support.str_to_integer
+    libc.src.errno.errno
 )
 
 add_entrypoint_object(
@@ -16,6 +17,7 @@
     strtoumax.h
   DEPENDS
     libc.src.__support.str_to_integer
+    libc.src.errno.errno
 )
 
 add_entrypoint_object(
diff --git a/libc/src/inttypes/strtoimax.cpp b/libc/src/inttypes/strtoimax.cpp
--- a/libc/src/inttypes/strtoimax.cpp
+++ b/libc/src/inttypes/strtoimax.cpp
@@ -9,6 +9,7 @@
 #include "src/inttypes/strtoimax.h"
 #include "src/__support/common.h"
 #include "src/__support/str_to_integer.h"
+#include "src/errno/libc_errno.h"
 
 namespace __llvm_libc {
 
@@ -17,7 +18,7 @@
                     int base)) {
   auto result = internal::strtointeger<intmax_t>(str, base);
   if (result.has_error())
-    errno = result.error;
+    libc_errno = result.error;
 
   if (str_end != nullptr)
     *str_end = const_cast<char *>(str + result.parsed_len);
diff --git a/libc/src/inttypes/strtoumax.cpp b/libc/src/inttypes/strtoumax.cpp
--- a/libc/src/inttypes/strtoumax.cpp
+++ b/libc/src/inttypes/strtoumax.cpp
@@ -9,6 +9,7 @@
 #include "src/inttypes/strtoumax.h"
 #include "src/__support/common.h"
 #include "src/__support/str_to_integer.h"
+#include "src/errno/libc_errno.h"
 
 namespace __llvm_libc {
 
@@ -17,7 +18,7 @@
                     int base)) {
   auto result = internal::strtointeger<uintmax_t>(str, base);
   if (result.has_error())
-    errno = result.error;
+    libc_errno = result.error;
 
   if (str_end != nullptr)
     *str_end = const_cast<char *>(str + result.parsed_len);
diff --git a/libc/src/sched/linux/CMakeLists.txt b/libc/src/sched/linux/CMakeLists.txt
--- a/libc/src/sched/linux/CMakeLists.txt
+++ b/libc/src/sched/linux/CMakeLists.txt
@@ -5,7 +5,6 @@
   HDRS
     ../sched_getaffinity.h
   DEPENDS
-    libc.include.errno
     libc.include.sched
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
@@ -18,7 +17,6 @@
   HDRS
     ../sched_setaffinity.h
   DEPENDS
-    libc.include.errno
     libc.include.sched
     libc.src.__support.OSUtil.osutil
     libc.src.errno.errno
diff --git a/libc/src/sched/linux/sched_getaffinity.cpp b/libc/src/sched/linux/sched_getaffinity.cpp
--- a/libc/src/sched/linux/sched_getaffinity.cpp
+++ b/libc/src/sched/linux/sched_getaffinity.cpp
@@ -10,8 +10,8 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
-#include <errno.h>
 #include <sched.h>
 #include <stdint.h>
 #include <sys/syscall.h> // For syscall numbers.
@@ -23,7 +23,7 @@
   long ret =
       __llvm_libc::syscall_impl(SYS_sched_getaffinity, tid, cpuset_size, mask);
   if (ret < 0) {
-    errno = -ret;
+    libc_errno = -ret;
     return -1;
   }
   if (size_t(ret) < cpuset_size) {
diff --git a/libc/src/sched/linux/sched_setaffinity.cpp b/libc/src/sched/linux/sched_setaffinity.cpp
--- a/libc/src/sched/linux/sched_setaffinity.cpp
+++ b/libc/src/sched/linux/sched_setaffinity.cpp
@@ -10,8 +10,8 @@
 
 #include "src/__support/OSUtil/syscall.h" // For internal syscall function.
 #include "src/__support/common.h"
+#include "src/errno/libc_errno.h"
 
-#include <errno.h>
 #include <sched.h>
 #include <sys/syscall.h> // For syscall numbers.
 
@@ -22,7 +22,7 @@
   long ret =
       __llvm_libc::syscall_impl(SYS_sched_setaffinity, tid, cpuset_size, mask);
   if (ret < 0) {
-    errno = -ret;
+    libc_errno = -ret;
     return -1;
   }
   return 0;
diff --git a/libc/test/src/dirent/CMakeLists.txt b/libc/test/src/dirent/CMakeLists.txt
--- a/libc/test/src/dirent/CMakeLists.txt
+++ b/libc/test/src/dirent/CMakeLists.txt
@@ -8,11 +8,11 @@
   SRCS
     dirent_test.cpp
   DEPENDS
-    libc.include.dirent
     libc.src.__support.CPP.string_view
     libc.src.dirent.closedir
     libc.src.dirent.dirfd
     libc.src.dirent.opendir
     libc.src.dirent.readdir
+    libc.src.errno.errno
 )
 
diff --git a/libc/test/src/dirent/dirent_test.cpp b/libc/test/src/dirent/dirent_test.cpp
--- a/libc/test/src/dirent/dirent_test.cpp
+++ b/libc/test/src/dirent/dirent_test.cpp
@@ -11,11 +11,11 @@
 #include "src/dirent/dirfd.h"
 #include "src/dirent/opendir.h"
 #include "src/dirent/readdir.h"
+#include "src/errno/libc_errno.h"
 
 #include "test/UnitTest/Test.h"
 
 #include <dirent.h>
-#include <errno.h>
 
 using string_view = __llvm_libc::cpp::string_view;
 
@@ -44,7 +44,7 @@
   }
 
   // Verify that we don't break out of the above loop in error.
-  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(libc_errno, 0);
 
   ASSERT_TRUE(file1 != nullptr);
   ASSERT_TRUE(file2 != nullptr);
@@ -55,17 +55,17 @@
 }
 
 TEST(LlvmLibcDirentTest, OpenNonExistentDir) {
-  errno = 0;
+  libc_errno = 0;
   ::DIR *dir = __llvm_libc::opendir("___xyz123__.non_existent__");
   ASSERT_TRUE(dir == nullptr);
-  ASSERT_EQ(errno, ENOENT);
-  errno = 0;
+  ASSERT_EQ(libc_errno, ENOENT);
+  libc_errno = 0;
 }
 
 TEST(LlvmLibcDirentTest, OpenFile) {
-  errno = 0;
+  libc_errno = 0;
   ::DIR *dir = __llvm_libc::opendir("testdata/file1.txt");
   ASSERT_TRUE(dir == nullptr);
-  ASSERT_EQ(errno, ENOTDIR);
-  errno = 0;
+  ASSERT_EQ(libc_errno, ENOTDIR);
+  libc_errno = 0;
 }
diff --git a/libc/test/src/fcntl/CMakeLists.txt b/libc/test/src/fcntl/CMakeLists.txt
--- a/libc/test/src/fcntl/CMakeLists.txt
+++ b/libc/test/src/fcntl/CMakeLists.txt
@@ -9,8 +9,8 @@
   SRCS
     creat_test.cpp
   DEPENDS
-    libc.include.errno
     libc.include.fcntl
+    libc.src.errno.errno
     libc.src.fcntl.creat
     libc.src.fcntl.open
     libc.src.unistd.close
@@ -24,8 +24,8 @@
   SRCS
     openat_test.cpp
   DEPENDS
-    libc.include.errno
     libc.include.fcntl
+    libc.src.errno.errno
     libc.src.fcntl.open
     libc.src.fcntl.openat
     libc.src.unistd.close
diff --git a/libc/test/src/fcntl/creat_test.cpp b/libc/test/src/fcntl/creat_test.cpp
--- a/libc/test/src/fcntl/creat_test.cpp
+++ b/libc/test/src/fcntl/creat_test.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/errno/libc_errno.h"
 #include "src/fcntl/creat.h"
 #include "src/fcntl/open.h"
 #include "src/unistd/close.h"
@@ -13,18 +14,16 @@
 #include "test/UnitTest/Test.h"
 #include "utils/testutils/FDReader.h"
 
-#include <errno.h>
-
 TEST(LlvmLibcCreatTest, CreatAndOpen) {
   using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
   constexpr const char *TEST_FILE = "testdata/creat.test";
   int fd = __llvm_libc::creat(TEST_FILE, S_IRWXU);
-  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(libc_errno, 0);
   ASSERT_GT(fd, 0);
   ASSERT_THAT(__llvm_libc::close(fd), Succeeds(0));
 
   fd = __llvm_libc::open(TEST_FILE, O_RDONLY);
-  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(libc_errno, 0);
   ASSERT_GT(fd, 0);
   ASSERT_THAT(__llvm_libc::close(fd), Succeeds(0));
 
diff --git a/libc/test/src/fcntl/openat_test.cpp b/libc/test/src/fcntl/openat_test.cpp
--- a/libc/test/src/fcntl/openat_test.cpp
+++ b/libc/test/src/fcntl/openat_test.cpp
@@ -6,6 +6,7 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "src/errno/libc_errno.h"
 #include "src/fcntl/open.h"
 #include "src/fcntl/openat.h"
 #include "src/unistd/close.h"
@@ -14,7 +15,6 @@
 #include "test/UnitTest/Test.h"
 #include "utils/testutils/FDReader.h"
 
-#include <errno.h>
 #include <fcntl.h>
 
 TEST(LlvmLibcUniStd, OpenAndReadTest) {
@@ -22,13 +22,13 @@
   constexpr const char *TEST_DIR = "testdata";
   constexpr const char *TEST_FILE = "openat.test";
   int dir_fd = __llvm_libc::open(TEST_DIR, O_DIRECTORY);
-  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(libc_errno, 0);
   ASSERT_GT(dir_fd, 0);
   constexpr const char TEST_MSG[] = "openat test";
   constexpr int TEST_MSG_SIZE = sizeof(TEST_MSG) - 1;
 
   int read_fd = __llvm_libc::openat(dir_fd, TEST_FILE, O_RDONLY);
-  ASSERT_EQ(errno, 0);
+  ASSERT_EQ(libc_errno, 0);
   ASSERT_GT(read_fd, 0);
   char read_buf[TEST_MSG_SIZE];
   ASSERT_THAT(__llvm_libc::read(read_fd, read_buf, TEST_MSG_SIZE),
diff --git a/libc/test/src/sched/CMakeLists.txt b/libc/test/src/sched/CMakeLists.txt
--- a/libc/test/src/sched/CMakeLists.txt
+++ b/libc/test/src/sched/CMakeLists.txt
@@ -7,10 +7,10 @@
   SRCS
     affinity_test.cpp
   DEPENDS
-    libc.include.errno
     libc.include.sched
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
     libc.src.sched.sched_getaffinity
     libc.src.sched.sched_setaffinity
     libc.test.errno_setter_matcher
@@ -23,10 +23,10 @@
   SRCS
     cpu_count_test.cpp
   DEPENDS
-    libc.include.errno
     libc.include.sched
     libc.include.sys_syscall
     libc.src.__support.OSUtil.osutil
+    libc.src.errno.errno
     libc.src.sched.sched_getaffinity
     libc.src.sched.__sched_getcpucount
     libc.test.errno_setter_matcher
diff --git a/libc/test/src/sched/affinity_test.cpp b/libc/test/src/sched/affinity_test.cpp
--- a/libc/test/src/sched/affinity_test.cpp
+++ b/libc/test/src/sched/affinity_test.cpp
@@ -7,17 +7,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/OSUtil/syscall.h"
+#include "src/errno/libc_errno.h"
 #include "src/sched/sched_getaffinity.h"
 #include "src/sched/sched_setaffinity.h"
 #include "test/ErrnoSetterMatcher.h"
 
-#include <errno.h>
 #include <sched.h>
 #include <sys/syscall.h>
 
 TEST(LlvmLibcSchedAffinityTest, SmokeTest) {
   cpu_set_t mask;
-  errno = 0;
+  libc_errno = 0;
   using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
   pid_t tid = __llvm_libc::syscall_impl(SYS_gettid);
   ASSERT_GT(tid, pid_t(0));
@@ -32,13 +32,13 @@
   using __llvm_libc::testing::ErrnoSetterMatcher::Fails;
   pid_t tid = __llvm_libc::syscall_impl(SYS_gettid);
 
-  errno = 0;
+  libc_errno = 0;
   ASSERT_THAT(__llvm_libc::sched_getaffinity(tid, sizeof(cpu_set_t), nullptr),
               Fails(EFAULT));
 
-  errno = 0;
+  libc_errno = 0;
   ASSERT_THAT(__llvm_libc::sched_setaffinity(tid, sizeof(cpu_set_t), nullptr),
               Fails(EFAULT));
 
-  errno = 0;
+  libc_errno = 0;
 }
diff --git a/libc/test/src/sched/cpu_count_test.cpp b/libc/test/src/sched/cpu_count_test.cpp
--- a/libc/test/src/sched/cpu_count_test.cpp
+++ b/libc/test/src/sched/cpu_count_test.cpp
@@ -7,17 +7,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/__support/OSUtil/syscall.h"
+#include "src/errno/libc_errno.h"
 #include "src/sched/sched_getaffinity.h"
 #include "src/sched/sched_getcpucount.h"
 #include "test/ErrnoSetterMatcher.h"
 
-#include <errno.h>
 #include <sched.h>
 #include <sys/syscall.h>
 
 TEST(LlvmLibcSchedAffinityTest, SmokeTest) {
   cpu_set_t mask;
-  errno = 0;
+  libc_errno = 0;
   using __llvm_libc::testing::ErrnoSetterMatcher::Succeeds;
   pid_t tid = __llvm_libc::syscall_impl(SYS_gettid);
   ASSERT_GT(tid, pid_t(0));