Move away from the __ARCH_WANT_SYSCALL_NO_AT system calls.

Modern architectures only get the *at(2) system calls. For example,
aarch64 doesn't have open(2), and expects userspace to use openat(2)
instead.

Change-Id: I87b4ed79790cb8a80844f5544ac1a13fda26c7b5
diff --git a/libc/bionic/utimes.cpp b/libc/bionic/utimes.cpp
new file mode 100644
index 0000000..315765a
--- /dev/null
+++ b/libc/bionic/utimes.cpp
@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+
+int utimes(const char* path, const timeval tv[2]) {
+  timespec ts[2];
+
+  // Whole seconds can just be copied.
+  ts[0].tv_sec = tv[0].tv_sec;
+  ts[1].tv_sec = tv[1].tv_sec;
+
+  // But we might overflow when converting microseconds to nanoseconds.
+  if (tv[0].tv_usec >= 1000000 || tv[0].tv_usec < 0 ||
+      tv[1].tv_usec >= 1000000 || tv[1].tv_usec < 0) {
+    errno = EINVAL;
+    return -1;
+  }
+  ts[0].tv_nsec = tv[0].tv_usec * 1000;
+  ts[1].tv_nsec = tv[1].tv_usec * 1000;
+
+  return utimensat(AT_FDCWD, path, ts, 0);
+}