Merge "envsetup.sh: Use prebuilt emulator binaries if available."

    unset ANDROID_HOST_OUT

    export ANDROID_HOST_OUT=$(get_abs_build_var HOST_OUT)

    # If prebuilts/android-emulator/<system>/ exists, prepend it to our PATH

    # to ensure that the corresponding 'emulator' binaries are used.

    case $(uname -s) in

        Darwin)

            ANDROID_EMULATOR_PREBUILTS=$T/prebuilts/android-emulator/darwin-x86_64

            ;;

        Linux)

            ANDROID_EMULATOR_PREBUILTS=$T/prebuilts/android-emulator/linux-x86_64

            ;;

        *)

            ANDROID_EMULATOR_PREBUILTS=

            ;;

    esac

    if [ -n "$ANDROID_EMULATOR_PREBUILTS" -a -d "$ANDROID_EMULATOR_PREBUILTS" ]; then

        PATH=$ANDROID_EMULATOR_PREBUILTS:$PATH

        export ANDROID_EMULATOR_PREBUILTS

    fi

    # needed for building linux on MacOS

    # TODO: fix the path

    #export HOST_EXTRACFLAGS="-I "$T/system/kernel_headers/host_include