Adds script for generating sysroot tarball from zephyr sdk. (#2490)

Signed-off-by: Jared <Jared.Woolston@gmail.com>

tools/scripts/update_zephyr.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+
+KONAN_TOOLCHAIN_VERSION=1
+TARBALL_zephyr_arm=target-sysroot-$KONAN_TOOLCHAIN_VERSION-zephyr-arm
+OUT=`pwd`
+
+if [ -z "ZEPHYR_SDK_INSTALL_DIR" ]; then
+    echo "Using default Zephyr SDK install location"
+    export ZEPHYR_SDK_INSTALL_DIR="/opt/zephyr-sdk"
+fi
+
+sdk=armv5-zephyr-eabi
+p=$ZEPHYR_SDK_INSTALL_DIR/sysroots/$sdk/usr
+echo "Packing SDK $sdk as $OUT/$TARBALL_zephyr_arm.tar.gz..."
+tar -czvf $OUT/$TARBALL_zephyr_arm.tar.gz -C $p .