Update LLVM from stable upstream (#1653)

Replace CheckedMalloc with upstream safe_malloc.

wpiutil/src/main/native/include/wpi/Errno.h

@@ -0,0 +1,38 @@
+//===- llvm/Support/Errno.h - Portable+convenient errno handling -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares some portable and convenient functions to deal with errno.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef WPIUTIL_WPI_ERRNO_H
+#define WPIUTIL_WPI_ERRNO_H
+
+#include <cerrno>
+#include <string>
+#include <type_traits>
+
+namespace wpi {
+namespace sys {
+
+template <typename FailT, typename Fun, typename... Args>
+inline auto RetryAfterSignal(const FailT &Fail, const Fun &F,
+                             const Args &... As) -> decltype(F(As...)) {
+  decltype(F(As...)) Res;
+  do {
+    errno = 0;
+    Res = F(As...);
+  } while (Res == Fail && errno == EINTR);
+  return Res;
+}
+
+}  // namespace sys
+}  // namespace wpi
+
+#endif  // WPIUTIL_WPI_ERRNO_H