add rx bare-metal toolchain support

scripts/create-menu

@@ -93,7 +93,7 @@ for arch in $(cat $topdir/target/arch.lst);do
 		alpha|ia64|sh|s390|tile|ppc64|mips64)
 		  printf "\tdepends on ADK_TARGET_OS_LINUX\n" >> $topdir/target/config/Config.in.arch.choice
 		  ;;
-		cr16|epiphany|m32r|mn10300|moxie|msp430|v850)
+		cr16|epiphany|m32r|mn10300|moxie|msp430|rx|v850)
 		  printf "\tdepends on ADK_TARGET_OS_BAREMETAL\n" >> $topdir/target/config/Config.in.arch.choice
 		  ;;
 	esac

target/arch.lst

@@ -27,6 +27,7 @@ nios2
 or1k
 ppc
 ppc64
+rx
 s390
 sparc
 sparc64

target/config/Config.in.cpu

@@ -970,6 +970,12 @@ config ADK_TARGET_CPU_PPC64_POWER8
 	select ADK_TARGET_WITH_MMU
 	depends on ADK_TARGET_ARCH_PPC64
 
+# rx
+config ADK_TARGET_CPU_RX
+	bool "rx"
+	select ADK_TARGET_WITHOUT_MMU
+	depends on ADK_TARGET_ARCH_RX
+
 # s390
 config ADK_TARGET_CPU_S390_Z900
 	bool "z900"
@@ -1985,6 +1991,7 @@ config ADK_TARGET_CPU_ARCH
 	default "ppc" if ADK_TARGET_ARCH_PPC
 	default "ppc64le" if ADK_TARGET_ARCH_PPC64 && ADK_TARGET_LITTLE_ENDIAN
 	default "ppc64" if ADK_TARGET_ARCH_PPC64 && ADK_TARGET_BIG_ENDIAN
+	default "rx" if ADK_TARGET_ARCH_RX
 	default "s390x" if ADK_TARGET_ARCH_S390
 	default "sh2" if ADK_TARGET_CPU_SH_SH2 && ADK_TARGET_LITTLE_ENDIAN
 	default "sh2eb" if ADK_TARGET_CPU_SH_SH2 && ADK_TARGET_BIG_ENDIAN

target/config/Config.in.libc

@@ -111,6 +111,7 @@ config ADK_TARGET_LIB_NEWLIB
 		ADK_TARGET_ARCH_NDS32 || \
 		ADK_TARGET_ARCH_OR1K || \
 		ADK_TARGET_ARCH_PPC || \
+		ADK_TARGET_ARCH_RX || \
 		ADK_TARGET_ARCH_SPARC || \
 		ADK_TARGET_ARCH_SPARC64 || \
 		ADK_TARGET_ARCH_V850 || \