In case this is handy for other people, here is how you can run Elixir on Android:

• Install https://termux.com/
• apt update; apt upgrade to have your system up to date.
• Install Erlang with apt install erlang, you should be able to run erl.
• (check if an Elixir package was created so you can avoid the trouble of the remaining lines )
• Install wget with apt install wget (otherwise you will get bad address on any wget request).
• Create a directory, and cd to it, for example: mkdir elixir; cd elixir.
• Download the precompiled package from the link named Precompiled.zip file for the latest release in the page http://elixir-lang.org/install.html#precompiled-package.At time of this writing the command wget https://github.com/elixir-lang/elixir/releases/download/v1.4.2/Precompiled.zip should do this.
• Unzip the files with unzip Precompiled.zip.
• Go to directory bin.
• Download the file termux-fix-shebang from the source at https://raw.githubusercontent.com/termux/termux-packages/master/packages/termux-tools/termux-fix-shebang. You can use wget https://raw.githubusercontent.com/termux/termux-packages/master/packages/termux-tools/termux-fix-shebang.
• Execute sh termux-fix-shebang elixir iex elixircin the bin directory (sh is required as the path of the shebang of the script is not compatible with termux).
• Execute which env and edit the first line of mix to set the path of command envto the one found by the command which.
• Add export PATH=$PATH:$HOME/elixir/bin to your .bashrc or execute the command on your terminal.
  You can then mix and iex. An Android phone is not exactly a convenient development platform, but it was useful to me to learn Elixir when waiting for whatever.