* Add build target 'darwin'
* Modify compiler options to work with clang
* Support 'jerry-libc' on Mac OS X
For MPU target build, install `gcc-arm-none-eabi` tool chain using `Homebrew` as following.
````
brew tap PX4/homebrew-px4
brew update
brew install gcc-arm-none-eabi
````
https://pixhawk.org/dev/toolchain_installation_mac
JerryScript-DCO-1.0-Signed-off-by: Sung-Jae Lee sjlee@mail.com
