diff -ruN gcc-7.1.0/gcc/config/riscv/rtems.h gcc-7.1.0-rtems/gcc/config/riscv/rtems.h
--- gcc-7.1.0/gcc/config/riscv/rtems.h	1970-01-01 10:00:00.000000000 +1000
+++ gcc-7.1.0-rtems/gcc/config/riscv/rtems.h	2017-05-29 20:01:29.981939603 +1000
@@ -0,0 +1,24 @@
+/* Definitions for RTEMS based ARM systems using EABI.
+   Copyright (C) 2011-2017 Free Software Foundation, Inc.
+ 
+   This file is part of GCC.
+ 
+   GCC 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, or (at your
+   option) any later version.
+ 
+   GCC 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 GCC; see the file COPYING3.  If not see
+   <http://www.gnu.org/licenses/>.  */
+
+
+#define TARGET_OS_CPP_BUILTINS() do {           \
+  builtin_define( "__rtems__" );                \
+  builtin_assert( "system=rtems" );             \
+} while (0)
diff -ruN gcc-7.1.0/gcc/config/riscv/t-rtems gcc-7.1.0-rtems/gcc/config/riscv/t-rtems
--- gcc-7.1.0/gcc/config/riscv/t-rtems	1970-01-01 10:00:00.000000000 +1000
+++ gcc-7.1.0-rtems/gcc/config/riscv/t-rtems	2017-05-29 18:27:16.476086251 +1000
@@ -0,0 +1 @@
+# Custom multilibs for RTEMS
diff -ruN gcc-7.1.0/gcc/config.gcc gcc-7.1.0-rtems/gcc/config.gcc
--- gcc-7.1.0/gcc/config.gcc	2017-03-25 00:59:51.000000000 +1100
+++ gcc-7.1.0-rtems/gcc/config.gcc	2017-05-29 19:58:06.896100190 +1000
@@ -2031,6 +2031,20 @@
 	# automatically detect that GAS supports it, yet we require it.
 	gcc_cv_initfini_array=yes
 	;;
+riscv*-*-rtems*)
+	tm_file="elfos.h newlib-stdint.h ${tm_file} riscv/elf.h riscv/rtems.h rtems.h"
+	case "x${enable_multilib}" in
+	xno) ;;
+	xyes) tmake_file="${tmake_file} riscv/t-elf-multilib" ;;
+	*) echo "Unknown value for enable_multilib"; exit 1
+	esac
+	tmake_file="${tmake_file} riscv/t-riscv riscv/t-rtems"
+	gnu_ld=yes
+	gas=yes
+	# Force .init_array support.  The configure script cannot always
+	# automatically detect that GAS supports it, yet we require it.
+	gcc_cv_initfini_array=yes
+	;;
 riscv*-*-elf*)
 	tm_file="elfos.h newlib-stdint.h ${tm_file} riscv/elf.h"
 	case "x${enable_multilib}" in