arch: Add support for RX GCC build

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

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "crosstool-ng"]
 	path = crosstool-ng
-	url = https://github.com/zephyrproject-rtos/crosstool-ng.git
+	url = https://github.com/renesas/crosstool-ng.git
 [submodule "binutils"]
 	path = binutils
 	url = https://github.com/zephyrproject-rtos/binutils-gdb.git
@@ -9,13 +9,13 @@
 	url = https://github.com/zephyrproject-rtos/newlib-cygwin.git
 [submodule "gcc"]
 	path = gcc
-	url = https://github.com/zephyrproject-rtos/gcc.git
+	url = https://github.com/renesas/gcc.git
 [submodule "gdb"]
 	path = gdb
 	url = https://github.com/zephyrproject-rtos/binutils-gdb.git
 [submodule "picolibc"]
 	path = picolibc
-	url = https://github.com/zephyrproject-rtos/picolibc.git
+	url = https://github.com/renesas/picolibc.git
 [submodule "crosskit-x86_64-apple-darwin"]
 	path = crosskit/crosskit-x86_64-apple-darwin
 	url = https://github.com/zephyrproject-rtos/crosskit-x86_64-apple-darwin.git

cmake/zephyr/target.cmake

@@ -10,6 +10,7 @@ set(CROSS_COMPILE_TARGET_arm64   aarch64-zephyr-elf)
 set(CROSS_COMPILE_TARGET_nios2     nios2-zephyr-elf)
 set(CROSS_COMPILE_TARGET_riscv   riscv64-zephyr-elf)
 set(CROSS_COMPILE_TARGET_mips       mips-zephyr-elf)
+set(CROSS_COMPILE_TARGET_rx           rx-zephyr-elf)
 set(CROSS_COMPILE_TARGET_microblaze microblazeel-zephyr-elf)
 set(CROSS_COMPILE_TARGET_xtensa   xtensa-${SOC_TOOLCHAIN_NAME}_zephyr-elf)
 

configs/rx-zephyr-elf.config

@@ -0,0 +1,6 @@
+CT_CONFIG_VERSION="3"
+CT_EXPERIMENTAL=y
+CT_ARCH_RX=y
+CT_TARGET_CFLAGS="-ftls-model=local-exec"
+CT_TARGET_VENDOR="zephyr"
+CT_MULTILIB=y