[rx] Support RX GCC Zephyr build

This commit add RX zephyr build config

Signed-off-by: Duy Nguyen <duy.nguyen.xa@renesas.com>

Author: duynguyenxa

gcc/config.gcc

@@ -3206,7 +3206,14 @@ rl78-*-elf*)
 	;;
 rx-*-elf*)
 	tm_file="dbxelf.h elfos.h newlib-stdint.h ${tm_file}"
-	tmake_file="${tmake_file} rx/t-rx"
+	case ${target} in
+	    rx-zephyr*)
+		tmake_file="${tmake_file} rx/t-zephyr"
+		;;
+	    *)
+	        tmake_file="${tmake_file} rx/t-rx"
+		;;
+	esac
 	extra_options="${extra_options} rx/elf.opt"
 	;;
 rx-*-linux*)

gcc/config/rx/t-zephyr

@@ -0,0 +1,37 @@
+# Makefile fragment for building GCC for the Renesas RX target.
+# Copyright (C) 2008-2022 Free Software Foundation, Inc.
+# Contributed by Red Hat.
+#
+# 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/>.
+
+# Enable multilibs:
+
+MULTILIB_OPTIONS    = m64bit-doubles  nofpu        mbig-endian-data  mpid
+MULTILIB_DIRNAMES   =  64-bit-double  no-fpu-libs   big-endian-data   pid
+
+# If necessary uncomment the next two lines to generate multilibs
+# using the old, broken, ABI.
+# MULTILIB_OPTIONS    += mgcc-abi
+# MULTILIB_DIRNAMES   +=  gcc-abi
+
+MULTILIB_OPTIONS   += mno-allow-string-insns
+MULTILIB_DIRNAMES  += no-strings
+
+MULTILIB_MATCHES    = nofpu=mnofpu  nofpu=mcpu?rx200  nofpu=mcpu?rx100
+
+MULTILIB_EXCEPTIONS =
+MULTILIB_EXTRA_OPTS =