I am hopping that Santa will bring me an ESP31 ( the prerelease model for ESP32).
Usually I create a VM for this. After I've installed the lumbuntu 15.04 in a Virtual Box and the Guest Addition now is time for compiler stuff.
The following commands are from espressif github with few modification for using the lumbutu i386 VM.
sudo apt-get install git autoconf build-essential gperf bison flex texinfo libtool libncurses5-dev wget gawk libc6-dev python-serial libexpat-dev libtool-bin
sudo mkdir /opt/Espressif
sudo chown $USER /opt/Espressif/
git clone -b esp108-1.21.0 git://github.com/jcmvbkbc/crosstool-NG.git
./bootstrap && ./configure --prefix=`pwd` && make && make install
The command ./ct-ng build takes some time(30-40minutes), so grab a coffee or a cup with tea.