TizenRT is lightweight RTOS-based platform to support low-end IoT devices.
Please find project details at Wiki especially documentations page.

Install the OS specific toolchain. Supported OS Type's are "linux" and "mac".
Get the build in binaries and libraries, gcc-arm-none-eabi-6-2017-q1-update-OS Type.tar.bz2
Untar the gcc-arm-none-eabi-6-2017-q1-update-OS Type.tar.bz2 and export the path like

tar xvjf gcc-arm-none-eabi-6-2017-q1-update-[OS Type].tar.bz2
export PATH=<Your Toolchain PATH>:$PATH

Be aware that recommanded toolchain is fully working on 64bits machine.

Get the build in binaries and libraries

64-bit Linux：

xtensa-esp32-elf-linux64-1.22.0-80-g6c4433a-5.2.0.tar.gz

32-bit Linux：

xtensa-esp32-elf-linux32-1.22.0-80-g6c4433a-5.2.0.tar.gz

tar xvjf xtensa-esp32-elf-[linux*]-1.22.0-80-g6c4433a-5.2.0.tar.gz
export PATH=<Your Toolchain PATH>:$PATH

git clone https://github.com/Samsung/TizenRT.git
cd TizenRT
TIZENRT_BASEDIR="$PWD"

Note: To contribute in this community, you need to clone your forked private repository instead.
Github guides this by working-with-forks.

Configure the build from $TIZENRT_BASEDIR/os/tools directory

cd os
./tools/configure.sh <board>/<configuration_set>

This command retrieves the specific pre-configured file named defconfig and Make.defs according to <board>/<configuration_set>.
You can see collection of all configuration files at $TIZENRT_BASEDIR/build/configs.
To check all pre-defined configurations, type as follows:

./configure.sh --help

After configuring above, configuration can be modified through make menuconfig from $TIZENRT_BASEDIR/os. Howerver, menuconfig isn't ready for Xtensa architecture esp32 board. Please do not use it for esp32 board.

cd ..
make menuconfig

Refer kconfig-frontend installation to use menuconfig.

Export your toolchain:

cd os
source setenv.sh <Your Toolchain PATH>

Or,

export PATH=<Your Toolchain PATH>:$PATH

Finally, initiate build by make from $TIZENRT_BASEDIR/os.

make

After compiling, "tinyara.bin" are built in the $TIZENRT_BASEDIR/build/ directory. Burn the image by performing the following commands in $TIZENRT_BASEDIR/os/:

Burn ALL the images:

cd $TIZENRT_BASEDIR/os
make download ALL

Burn the bootloader:

cd $TIZENRT_BASEDIR/os
make download BOOTLOADER

Burn the TizenRT image:

cd $TIZENRT_BASEDIR/os
make download APP