avr-libc software package provides Standard C library for Atmel AVR development, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install avr-libc
avr-libc is installed in your system.
Make ensure the avr-libc package were installed using the commands given below,
$ sudo dpkg-query -l | grep avr-libc *
You will get with avr-libc package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | Other OSs and file systems |
| Package | avr-libc |
| Version | 1:1.8.0+Atmel3.5.0-1 |
| Description | Standard C library for Atmel AVR development |
| Sub Section | otherosfs |