diff --git a/grub-lakitu/INSTALL b/grub-lakitu/INSTALL
index f3c20ed..f8bd911 100644
--- a/grub-lakitu/INSTALL
+++ b/grub-lakitu/INSTALL
@@ -11,27 +11,9 @@
 you don't have any of them, please obtain and install them before
 configuring the GRUB.
 
-* GCC 4.1.3 or later
-  Note: older versions may work but support is limited
-
-  Experimental support for clang 3.3 or later (results in much bigger binaries)
+* GCC 5.1.0 or later
+  Experimental support for clang 3.8.0 or later (results in much bigger binaries)
   for i386, x86_64, arm (including thumb), arm64, mips(el), powerpc, sparc64
-  Note: clang 3.2 or later works for i386 and x86_64 targets but results in
-        much bigger binaries.
-	earlier versions not tested
-  Note: clang 3.2 or later works for arm
-	earlier versions not tested
-  Note: clang on arm64 is not supported due to
-	https://llvm.org/bugs/show_bug.cgi?id=26030
-  Note: clang 3.3 or later works for mips(el)
-	earlier versions fail to generate .reginfo and hence gprel relocations
-	fail.
-  Note: clang 3.2 or later works for powerpc
-	earlier versions not tested
-  Note: clang 3.5 or later works for sparc64
-        earlier versions return "error: unable to interface with target machine"
-  Note: clang has no support for ia64 and hence you can't compile GRUB
-	for ia64 with clang
 * GNU Make
 * GNU Bison 2.3 or later
 * GNU gettext 0.17 or later
diff --git a/grub-lakitu/include/grub/compiler.h b/grub-lakitu/include/grub/compiler.h
index c9e1d7a..8f3be3a 100644
--- a/grub-lakitu/include/grub/compiler.h
+++ b/grub-lakitu/include/grub/compiler.h
@@ -48,4 +48,12 @@
 #  define WARN_UNUSED_RESULT
 #endif
 
+#if defined(__clang__) && defined(__clang_major__) && defined(__clang_minor__)
+#  define CLANG_PREREQ(maj,min) \
+          ((__clang_major__ > (maj)) || \
+	   (__clang_major__ == (maj) && __clang_minor__ >= (min)))
+#else
+#  define CLANG_PREREQ(maj,min) 0
+#endif
+
 #endif /* ! GRUB_COMPILER_HEADER */
diff --git a/grub-lakitu/include/grub/safemath.h b/grub-lakitu/include/grub/safemath.h
new file mode 100644
index 0000000..c17b89b
--- /dev/null
+++ b/grub-lakitu/include/grub/safemath.h
@@ -0,0 +1,37 @@
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2020  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *  Arithmetic operations that protect against overflow.
+ */
+
+#ifndef GRUB_SAFEMATH_H
+#define GRUB_SAFEMATH_H 1
+
+#include <grub/compiler.h>
+
+/* These appear in gcc 5.1 and clang 3.8. */
+#if GNUC_PREREQ(5, 1) || CLANG_PREREQ(3, 8)
+
+#define grub_add(a, b, res)	__builtin_add_overflow(a, b, res)
+#define grub_sub(a, b, res)	__builtin_sub_overflow(a, b, res)
+#define grub_mul(a, b, res)	__builtin_mul_overflow(a, b, res)
+
+#else
+#error gcc 5.1 or newer or clang 3.8 or newer is required
+#endif
+
+#endif /* GRUB_SAFEMATH_H */