ArmPkg/Library/CompilerIntrinsicsLib: Enable VS2017/ARM builds

Introduce CRT assembly replacements for __rt_sdiv, __rt_udiv,
__rt_udiv64, __rt_sdiv64, __rt_srsh (by reusing the RVCT code)
as well as memcpy and memset.
For MSFT compatibility, some of the code needs to be explicitly
forced to ARM, and the /oldit assembly flag needs to be added.
Also, while RVCT_ASM_EXPORT macro invocations have been removed,
the replacement code is designed to be as close as possible to
the one that would have been generated if using the macros.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

ArmPkg/Library/CompilerIntrinsicsLib/memcpy_ms.c

@@ -0,0 +1,34 @@
+//------------------------------------------------------------------------------
+//
+// Copyright (c) 2017, Pete Batard. All rights reserved.<BR>
+//
+// This program and the accompanying materials are licensed and made
+// available under the terms and conditions of the BSD License which
+// accompanies this distribution.  The full text of the license may be
+// found at http://opensource.org/licenses/bsd-license.php
+//
+// THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+// WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR
+// IMPLIED.
+//
+//------------------------------------------------------------------------------
+
+#if defined(_M_ARM64)
+typedef unsigned __int64  size_t;
+#else
+typedef unsigned __int32  size_t;
+#endif
+
+void* memcpy(void *, const void *, size_t);
+#pragma intrinsic(memcpy)
+#pragma function(memcpy)
+void* memcpy(void *dest, const void *src, size_t n)
+{
+  unsigned char *d = dest;
+  unsigned char const *s = src;
+
+  while (n--)
+    *d++ = *s++;
+
+  return dest;
+}