$ sudo apt-get update
$ sudo apt-get install libgl1-mesa-swx11-i686 

libgl1-mesa-swx11-i686 is installed in your system.

Make ensure the libgl1-mesa-swx11-i686 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libgl1-mesa-swx11-i686 *

You will get with libgl1-mesa-swx11-i686 package name, version, architecture and description in a table

libgl1-mesa-swx11-i686 package basic information: