esp-open-sdk generates a complete toolchain to build native firmware applications. Further information can be found on its GitHub Project Page.

For distributions based on Debian (e.g. Ubuntu/Mint):

 sudo apt-get install make unrar autoconf automake libtool gcc g++ gperf \
   flex bison texinfo gawk ncurses-dev libexpat-dev python sed git

add libtool-bin if using Debian8/Jessie.

 git clone https://github.com/pfalcon/esp-open-sdk.git
 cd esp-open-sdk
 make STANDALONE=y

Note: If you set STANDALONE=y, the current Espressif SDK will be directly integrated into your toolchain. This eases the development, but makes it difficult to upgrade SDK versions later on. Set STANDALONE=n if you want to separate the SDK.

To call the generated xtensa-lx106-* binaries, you have to add the toolchain to your PATH. You can either set PATH on every new terminal session:

 export PATH=[your esp-open-sdk directory]/bin:$PATH

To make this change permanent add the above line to your .profile file in your home directory.