[libc] Fix the remaining old style includes

[phosek]

Summary

These were omitted from previous cleanup changes.

libc/src/__support/threads/linux/callonce.cpp

 //===-- Linux implementation of the callonce function ---------------------===//
 //
 // 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 "futex_word.h"
 
-#include "include/sys/syscall.h" // For syscall numbers.
 #include "src/__support/CPP/atomic.h"
 #include "src/__support/OSUtil/syscall.h" // For syscall functions.
 #include "src/__support/threads/callonce.h"
 
 #include <limits.h>
 #include <linux/futex.h>
+#include <sys/syscall.h> // For syscall numbers.
 
 namespace __llvm_libc {
 
 static constexpr FutexWordType NOT_CALLED = 0x0;
 static constexpr FutexWordType START = 0x11;
 static constexpr FutexWordType WAITING = 0x22;
 static constexpr FutexWordType FINISH = 0x33;
 

libc/src/signal/linux/__restore.cpp

 //===-- Linux implementation of __restore_rt ------------------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 
 // This file is implemented separately from sigaction.cpp so that we can
 // strongly control the options this file is compiled with. __restore_rt cannot
 // make any stack allocations so we must ensure this.
 
-#include "include/sys/syscall.h"
 #include "src/__support/OSUtil/syscall.h"
 
+#include <sys/syscall.h>
+
 namespace __llvm_libc {
 
 extern "C" void __restore_rt()
     __attribute__((no_sanitize("all"),
                    hidden));
 
 extern "C" void __restore_rt() {
   __llvm_libc::syscall_impl<long>(SYS_rt_sigreturn);
 }
 
 } // namespace __llvm_libc

libc/src/threads/linux/call_once.cpp

 //===-- Linux implementation of the call_once function --------------------===//
 //
 // 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 "Futex.h"
 
-#include "include/sys/syscall.h" // For syscall numbers.
-#include "include/threads.h"     // For call_once related type definition.
 #include "src/__support/CPP/atomic.h"
 #include "src/__support/OSUtil/syscall.h" // For syscall functions.
 #include "src/__support/common.h"
 #include "src/threads/call_once.h"
 #include "src/threads/linux/Futex.h"
 
 #include <limits.h>
 #include <linux/futex.h>
+#include <sys/syscall.h> // For syscall numbers.
+#include <threads.h>     // For call_once related type definition.
 
 namespace __llvm_libc {
 
 static constexpr FutexWordType START = 0x11;
 static constexpr FutexWordType WAITING = 0x22;
 static constexpr FutexWordType FINISH = 0x33;
 static constexpr once_flag ONCE_FLAG_INIT_VAL = ONCE_FLAG_INIT;