diff --git a/lib/compiler-rt/builtins/int_lib.h b/lib/compiler-rt/builtins/int_lib.h
new file mode 100644
index 0000000..724d5a4
--- /dev/null
+++ b/lib/compiler-rt/builtins/int_lib.h
@@ -0,0 +1,124 @@
+/* ===-- int_lib.h - configuration header for compiler-rt  -----------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file is a configuration header for compiler-rt.
+ * This file is not part of the interface of this library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+/*
+ * Portions copyright (c) 2018, ARM Limited and Contributors.
+ * All rights reserved.
+ */
+
+#ifndef INT_LIB_H
+#define INT_LIB_H
+
+/* Assumption: Signed integral is 2's complement. */
+/* Assumption: Right shift of signed negative is arithmetic shift. */
+/* Assumption: Endianness is little or big (not mixed). */
+
+#if defined(__ELF__)
+#define FNALIAS(alias_name, original_name) \
+  void alias_name() __attribute__((__alias__(#original_name)))
+#define COMPILER_RT_ALIAS(aliasee) __attribute__((__alias__(#aliasee)))
+#else
+#define FNALIAS(alias, name) _Pragma("GCC error(\"alias unsupported on this file format\")")
+#define COMPILER_RT_ALIAS(aliasee) _Pragma("GCC error(\"alias unsupported on this file format\")")
+#endif
+
+/* ABI macro definitions */
+
+#if __ARM_EABI__
+# ifdef COMPILER_RT_ARMHF_TARGET
+#   define COMPILER_RT_ABI
+# else
+#   define COMPILER_RT_ABI __attribute__((__pcs__("aapcs")))
+# endif
+#else
+# define COMPILER_RT_ABI
+#endif
+
+#define AEABI_RTABI __attribute__((__pcs__("aapcs")))
+
+#ifdef _MSC_VER
+#define ALWAYS_INLINE __forceinline
+#define NOINLINE __declspec(noinline)
+#define NORETURN __declspec(noreturn)
+#define UNUSED
+#else
+#define ALWAYS_INLINE __attribute__((always_inline))
+#define NOINLINE __attribute__((noinline))
+#define NORETURN __attribute__((noreturn))
+#define UNUSED __attribute__((unused))
+#endif
+
+#include <sys/limits.h>
+#include <sys/stdint.h>
+#include <sys/types.h>
+
+/* Include the commonly used internal type definitions. */
+#include "int_types.h"
+
+COMPILER_RT_ABI si_int __paritysi2(si_int a);
+COMPILER_RT_ABI si_int __paritydi2(di_int a);
+
+COMPILER_RT_ABI di_int __divdi3(di_int a, di_int b);
+COMPILER_RT_ABI si_int __divsi3(si_int a, si_int b);
+COMPILER_RT_ABI su_int __udivsi3(su_int n, su_int d);
+
+COMPILER_RT_ABI su_int __udivmodsi4(su_int a, su_int b, su_int* rem);
+COMPILER_RT_ABI du_int __udivmoddi4(du_int a, du_int b, du_int* rem);
+#ifdef CRT_HAS_128BIT
+COMPILER_RT_ABI si_int __clzti2(ti_int a);
+COMPILER_RT_ABI tu_int __udivmodti4(tu_int a, tu_int b, tu_int* rem);
+#endif
+
+/* Definitions for builtins unavailable on MSVC */
+#if defined(_MSC_VER) && !defined(__clang__)
+#include <intrin.h>
+
+uint32_t __inline __builtin_ctz(uint32_t value) {
+  unsigned long trailing_zero = 0;
+  if (_BitScanForward(&trailing_zero, value))
+    return trailing_zero;
+  return 32;
+}
+
+uint32_t __inline __builtin_clz(uint32_t value) {
+  unsigned long leading_zero = 0;
+  if (_BitScanReverse(&leading_zero, value))
+    return 31 - leading_zero;
+  return 32;
+}
+
+#if defined(_M_ARM) || defined(_M_X64)
+uint32_t __inline __builtin_clzll(uint64_t value) {
+  unsigned long leading_zero = 0;
+  if (_BitScanReverse64(&leading_zero, value))
+    return 63 - leading_zero;
+  return 64;
+}
+#else
+uint32_t __inline __builtin_clzll(uint64_t value) {
+  if (value == 0)
+    return 64;
+  uint32_t msh = (uint32_t)(value >> 32);
+  uint32_t lsh = (uint32_t)(value & 0xFFFFFFFF);
+  if (msh != 0)
+    return __builtin_clz(msh);
+  return 32 + __builtin_clz(lsh);
+}
+#endif
+
+#define __builtin_clzl __builtin_clzll
+#endif /* defined(_MSC_VER) && !defined(__clang__) */
+
+#endif /* INT_LIB_H */