build both gcc and xcode

jenkins/osx_xcode_native.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# Copyright (c) Microsoft. All rights reserved.
+# Licensed under the MIT license. See LICENSE file in the project root for full license information.
+#
+
+set -e
+
+script_dir=$(cd "$(dirname "$0")" && pwd)
+build_root=$(cd "${script_dir}/.." && pwd)
+build_folder=$build_root"/cmake"
+
+CORES=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || sysctl -n hw.ncpu)
+
+rm -r -f $build_folder
+mkdir -p $build_folder
+pushd $build_folder
+cmake .. -Drun_unittests:bool=ON -G Xcode
+cmake --build . -- --jobs=$CORES
+ctest -C "debug" -V
+popd