diff --git a/libc/src/assert/__assert_fail.cpp b/libc/src/assert/__assert_fail.cpp
--- a/libc/src/assert/__assert_fail.cpp
+++ b/libc/src/assert/__assert_fail.cpp
@@ -11,7 +11,7 @@
 
 // These includes are temporary.
 #include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
+#include <sys/syscall.h>          // For syscall numbers.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/math/cosf.cpp b/libc/src/math/cosf.cpp
--- a/libc/src/math/cosf.cpp
+++ b/libc/src/math/cosf.cpp
@@ -9,8 +9,8 @@
 #include "math_utils.h"
 #include "sincosf_utils.h"
 
-#include "include/math.h"
 #include "src/__support/common.h"
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/math/exp2f.cpp b/libc/src/math/exp2f.cpp
--- a/libc/src/math/exp2f.cpp
+++ b/libc/src/math/exp2f.cpp
@@ -9,8 +9,8 @@
 #include "exp_utils.h"
 #include "math_utils.h"
 
-#include "include/math.h"
 #include "src/__support/common.h"
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/math/expf.cpp b/libc/src/math/expf.cpp
--- a/libc/src/math/expf.cpp
+++ b/libc/src/math/expf.cpp
@@ -9,8 +9,8 @@
 #include "exp_utils.h"
 #include "math_utils.h"
 
-#include "include/math.h"
 #include "src/__support/common.h"
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/math/math_utils.h b/libc/src/math/math_utils.h
--- a/libc/src/math/math_utils.h
+++ b/libc/src/math/math_utils.h
@@ -9,11 +9,11 @@
 #ifndef LLVM_LIBC_SRC_MATH_MATH_UTILS_H
 #define LLVM_LIBC_SRC_MATH_MATH_UTILS_H
 
-#include "include/errno.h"
-#include "include/math.h"
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 #include "utils/CPP/TypeTraits.h"
+#include <errno.h>
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/math/sincosf.cpp b/libc/src/math/sincosf.cpp
--- a/libc/src/math/sincosf.cpp
+++ b/libc/src/math/sincosf.cpp
@@ -9,8 +9,8 @@
 #include "math_utils.h"
 #include "sincosf_utils.h"
 
-#include "include/math.h"
 #include "src/__support/common.h"
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/math/sinf.cpp b/libc/src/math/sinf.cpp
--- a/libc/src/math/sinf.cpp
+++ b/libc/src/math/sinf.cpp
@@ -9,8 +9,8 @@
 #include "math_utils.h"
 #include "sincosf_utils.h"
 
-#include "include/math.h"
 #include "src/__support/common.h"
+#include <math.h>
 
 #include <stdint.h>
 
diff --git a/libc/src/signal/linux/__restore.cpp b/libc/src/signal/linux/__restore.cpp
--- a/libc/src/signal/linux/__restore.cpp
+++ b/libc/src/signal/linux/__restore.cpp
@@ -11,7 +11,7 @@
 // make any stack allocations so we must ensure this.
 
 #include "config/linux/syscall.h"
-#include "include/sys/syscall.h"
+#include <sys/syscall.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/linux/sigaddset.cpp b/libc/src/signal/linux/sigaddset.cpp
--- a/libc/src/signal/linux/sigaddset.cpp
+++ b/libc/src/signal/linux/sigaddset.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/signal/sigaddset.h"
-#include "include/errno.h" // For E* macros.
 #include "src/errno/llvmlibc_errno.h"
 #include "src/signal/linux/signal.h"
+#include <errno.h> // For E* macros.
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/signal/linux/sigdelset.cpp b/libc/src/signal/linux/sigdelset.cpp
--- a/libc/src/signal/linux/sigdelset.cpp
+++ b/libc/src/signal/linux/sigdelset.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/signal/sigdelset.h"
-#include "include/errno.h"
 #include "src/errno/llvmlibc_errno.h"
 #include "src/signal/linux/signal.h"
+#include <errno.h>
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/signal/linux/sigemptyset.cpp b/libc/src/signal/linux/sigemptyset.cpp
--- a/libc/src/signal/linux/sigemptyset.cpp
+++ b/libc/src/signal/linux/sigemptyset.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/signal/sigemptyset.h"
-#include "include/errno.h" // For E* macros.
 #include "src/errno/llvmlibc_errno.h"
 #include "src/signal/linux/signal.h"
+#include <errno.h> // For E* macros.
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/signal/linux/sigfillset.cpp b/libc/src/signal/linux/sigfillset.cpp
--- a/libc/src/signal/linux/sigfillset.cpp
+++ b/libc/src/signal/linux/sigfillset.cpp
@@ -7,9 +7,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "src/signal/sigfillset.h"
-#include "include/errno.h"
 #include "src/errno/llvmlibc_errno.h"
 #include "src/signal/linux/signal.h"
+#include <errno.h>
 
 #include "src/__support/common.h"
 
diff --git a/libc/src/signal/raise.h b/libc/src/signal/raise.h
--- a/libc/src/signal/raise.h
+++ b/libc/src/signal/raise.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_RAISE_H
 #define LLVM_LIBC_SRC_SIGNAL_RAISE_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigaction.h b/libc/src/signal/sigaction.h
--- a/libc/src/signal/sigaction.h
+++ b/libc/src/signal/sigaction.h
@@ -10,7 +10,7 @@
 #define LLVM_LIBC_SRC_SIGNAL_SIGACTION_H
 
 #define __LLVM_LIBC_INTERNAL_SIGACTION
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigaddset.h b/libc/src/signal/sigaddset.h
--- a/libc/src/signal/sigaddset.h
+++ b/libc/src/signal/sigaddset.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGEADDSET_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGEADDSET_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigdelset.h b/libc/src/signal/sigdelset.h
--- a/libc/src/signal/sigdelset.h
+++ b/libc/src/signal/sigdelset.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGDELSET_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGDELSET_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigemptyset.h b/libc/src/signal/sigemptyset.h
--- a/libc/src/signal/sigemptyset.h
+++ b/libc/src/signal/sigemptyset.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGEMPTYSET_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGEMPTYSET_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigfillset.h b/libc/src/signal/sigfillset.h
--- a/libc/src/signal/sigfillset.h
+++ b/libc/src/signal/sigfillset.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGFILLSET_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGFILLSET_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/signal.h b/libc/src/signal/signal.h
--- a/libc/src/signal/signal.h
+++ b/libc/src/signal/signal.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGNAL_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGNAL_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/signal/sigprocmask.h b/libc/src/signal/sigprocmask.h
--- a/libc/src/signal/sigprocmask.h
+++ b/libc/src/signal/sigprocmask.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SIGNAL_SIGPROCMASK_H
 #define LLVM_LIBC_SRC_SIGNAL_SIGPROCMASK_H
 
-#include "include/signal.h"
+#include <signal.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/stdio/FILE.h b/libc/src/stdio/FILE.h
--- a/libc/src/stdio/FILE.h
+++ b/libc/src/stdio/FILE.h
@@ -9,8 +9,8 @@
 #ifndef LLVM_LIBC_SRC_STDIO_FILE_H
 #define LLVM_LIBC_SRC_STDIO_FILE_H
 
-#include "include/threads.h"
 #include <stddef.h>
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/stdlib/linux/_Exit.cpp b/libc/src/stdlib/linux/_Exit.cpp
--- a/libc/src/stdlib/linux/_Exit.cpp
+++ b/libc/src/stdlib/linux/_Exit.cpp
@@ -7,8 +7,8 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
 #include "src/__support/common.h"
+#include <sys/syscall.h> // For syscall numbers.
 
 #include "src/stdlib/_Exit.h"
 
diff --git a/libc/src/string/strcat.h b/libc/src/string/strcat.h
--- a/libc/src/string/strcat.h
+++ b/libc/src/string/strcat.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STRING_STRCAT_H
 #define LLVM_LIBC_SRC_STRING_STRCAT_H
 
-#include "include/string.h"
+#include <string.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/string/strcpy.h b/libc/src/string/strcpy.h
--- a/libc/src/string/strcpy.h
+++ b/libc/src/string/strcpy.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STRING_STRCPY_H
 #define LLVM_LIBC_SRC_STRING_STRCPY_H
 
-#include "include/string.h"
+#include <string.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/string/strlen.h b/libc/src/string/strlen.h
--- a/libc/src/string/strlen.h
+++ b/libc/src/string/strlen.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_STRING_STRLEN_H
 #define LLVM_LIBC_SRC_STRING_STRLEN_H
 
-#include "include/string.h"
+#include <string.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/sys/mman/linux/mmap.cpp b/libc/src/sys/mman/linux/mmap.cpp
--- a/libc/src/sys/mman/linux/mmap.cpp
+++ b/libc/src/sys/mman/linux/mmap.cpp
@@ -9,9 +9,9 @@
 #include "src/sys/mman/mmap.h"
 
 #include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
 
 #include <linux/param.h> // For EXEC_PAGESIZE.
 
diff --git a/libc/src/sys/mman/linux/munmap.cpp b/libc/src/sys/mman/linux/munmap.cpp
--- a/libc/src/sys/mman/linux/munmap.cpp
+++ b/libc/src/sys/mman/linux/munmap.cpp
@@ -9,9 +9,9 @@
 #include "src/sys/mman/munmap.h"
 
 #include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/sys/mman/mmap.h b/libc/src/sys/mman/mmap.h
--- a/libc/src/sys/mman/mmap.h
+++ b/libc/src/sys/mman/mmap.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SYS_MMAN_MMAP_H
 #define LLVM_LIBC_SRC_SYS_MMAN_MMAP_H
 
-#include "include/sys/mman.h" // For size_t and off_t
+#include <sys/mman.h> // For size_t and off_t
 
 namespace __llvm_libc {
 
diff --git a/libc/src/sys/mman/munmap.h b/libc/src/sys/mman/munmap.h
--- a/libc/src/sys/mman/munmap.h
+++ b/libc/src/sys/mman/munmap.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_SYS_MMAN_MUNMAP_H
 #define LLVM_LIBC_SRC_SYS_MMAN_MUNMAP_H
 
-#include "include/sys/mman.h" // For size_t.
+#include <sys/mman.h> // For size_t.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/call_once.h b/libc/src/threads/call_once.h
--- a/libc/src/threads/call_once.h
+++ b/libc/src/threads/call_once.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_CALL_ONCE_H
 #define LLVM_LIBC_SRC_THREADS_CALL_ONCE_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/linux/call_once.cpp b/libc/src/threads/linux/call_once.cpp
--- a/libc/src/threads/linux/call_once.cpp
+++ b/libc/src/threads/linux/call_once.cpp
@@ -7,10 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For call_once related type definition.
 #include "src/__support/common.h"
 #include "src/threads/linux/thread_utils.h"
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For call_once related type definition.
 
 #include <limits.h>
 #include <linux/futex.h>
diff --git a/libc/src/threads/linux/mtx_init.cpp b/libc/src/threads/linux/mtx_init.cpp
--- a/libc/src/threads/linux/mtx_init.cpp
+++ b/libc/src/threads/linux/mtx_init.cpp
@@ -6,9 +6,9 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "include/threads.h" // For mtx_t definition.
 #include "src/__support/common.h"
 #include "src/threads/linux/thread_utils.h"
+#include <threads.h> // For mtx_t definition.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/linux/mtx_lock.cpp b/libc/src/threads/linux/mtx_lock.cpp
--- a/libc/src/threads/linux/mtx_lock.cpp
+++ b/libc/src/threads/linux/mtx_lock.cpp
@@ -7,10 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For mtx_t definition.
 #include "src/__support/common.h"
 #include "src/threads/linux/thread_utils.h"
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For mtx_t definition.
 
 #include <linux/futex.h> // For futex operations.
 #include <stdatomic.h>   // For atomic_compare_exchange_strong.
diff --git a/libc/src/threads/linux/mtx_unlock.cpp b/libc/src/threads/linux/mtx_unlock.cpp
--- a/libc/src/threads/linux/mtx_unlock.cpp
+++ b/libc/src/threads/linux/mtx_unlock.cpp
@@ -7,10 +7,10 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For syscall functions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For mtx_t definition.
 #include "src/__support/common.h"
 #include "src/threads/linux/thread_utils.h"
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For mtx_t definition.
 
 #include <linux/futex.h> // For futex operations.
 #include <stdatomic.h>   // for atomic_compare_exchange_strong.
diff --git a/libc/src/threads/linux/thrd_create.cpp b/libc/src/threads/linux/thrd_create.cpp
--- a/libc/src/threads/linux/thrd_create.cpp
+++ b/libc/src/threads/linux/thrd_create.cpp
@@ -7,15 +7,15 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For syscall function.
-#include "include/errno.h"        // For E* error values.
-#include "include/sys/mman.h"     // For PROT_* and MAP_* definitions.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For thrd_* type definitions.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
 #include "src/sys/mman/mmap.h"
 #include "src/sys/mman/munmap.h"
 #include "src/threads/linux/thread_utils.h"
+#include <errno.h>       // For E* error values.
+#include <sys/mman.h>    // For PROT_* and MAP_* definitions.
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For thrd_* type definitions.
 
 #include <linux/futex.h> // For futex operations.
 #include <linux/sched.h> // For CLONE_* flags.
diff --git a/libc/src/threads/linux/thrd_join.cpp b/libc/src/threads/linux/thrd_join.cpp
--- a/libc/src/threads/linux/thrd_join.cpp
+++ b/libc/src/threads/linux/thrd_join.cpp
@@ -7,11 +7,11 @@
 //===----------------------------------------------------------------------===//
 
 #include "config/linux/syscall.h" // For syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
-#include "include/threads.h"      // For thrd_* type definitions.
 #include "src/__support/common.h"
 #include "src/sys/mman/munmap.h"
 #include "src/threads/linux/thread_utils.h"
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For thrd_* type definitions.
 
 #include <linux/futex.h> // For futex operations.
 #include <stdatomic.h>   // For atomic_load.
diff --git a/libc/src/threads/mtx_init.h b/libc/src/threads/mtx_init.h
--- a/libc/src/threads/mtx_init.h
+++ b/libc/src/threads/mtx_init.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_MTX_INIT_H
 #define LLVM_LIBC_SRC_THREADS_MTX_INIT_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/mtx_lock.h b/libc/src/threads/mtx_lock.h
--- a/libc/src/threads/mtx_lock.h
+++ b/libc/src/threads/mtx_lock.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_MTX_LOCK_H
 #define LLVM_LIBC_SRC_THREADS_MTX_LOCK_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/mtx_unlock.h b/libc/src/threads/mtx_unlock.h
--- a/libc/src/threads/mtx_unlock.h
+++ b/libc/src/threads/mtx_unlock.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_MTX_UNLOCK_H
 #define LLVM_LIBC_SRC_THREADS_MTX_UNLOCK_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/thrd_create.h b/libc/src/threads/thrd_create.h
--- a/libc/src/threads/thrd_create.h
+++ b/libc/src/threads/thrd_create.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_THRD_CREATE_H
 #define LLVM_LIBC_SRC_THREADS_THRD_CREATE_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/threads/thrd_join.h b/libc/src/threads/thrd_join.h
--- a/libc/src/threads/thrd_join.h
+++ b/libc/src/threads/thrd_join.h
@@ -9,7 +9,7 @@
 #ifndef LLVM_LIBC_SRC_THREADS_THRD_JOIN_H
 #define LLVM_LIBC_SRC_THREADS_THRD_JOIN_H
 
-#include "include/threads.h"
+#include <threads.h>
 
 namespace __llvm_libc {
 
diff --git a/libc/src/unistd/linux/write.cpp b/libc/src/unistd/linux/write.cpp
--- a/libc/src/unistd/linux/write.cpp
+++ b/libc/src/unistd/linux/write.cpp
@@ -9,9 +9,9 @@
 #include "src/unistd/write.h"
 
 #include "config/linux/syscall.h" // For internal syscall function.
-#include "include/sys/syscall.h"  // For syscall numbers.
 #include "src/__support/common.h"
 #include "src/errno/llvmlibc_errno.h"
+#include <sys/syscall.h> // For syscall numbers.
 
 namespace __llvm_libc {
 
diff --git a/libc/src/unistd/write.h b/libc/src/unistd/write.h
--- a/libc/src/unistd/write.h
+++ b/libc/src/unistd/write.h
@@ -9,8 +9,8 @@
 #ifndef LLVM_LIBC_SRC_UNISTD_WRITE_H
 #define LLVM_LIBC_SRC_UNISTD_WRITE_H
 
-#include "include/unistd.h"
 #include <stddef.h>
+#include <unistd.h>
 
 namespace __llvm_libc {