Plz disregard my post as follows due to I will submit an issue on the appropriate github site.
I'm joining in on this thread - I get the same Arduino-builder error trying to compile for the uno board:
avr-g++: error: cannot access device-specs for ‘atmega328p’ expected at ‘device-specs/specs-atmega328p’
Compiled sketch is to be loaded into the uno by arduino-builder, not the IDE b/c I'm not using a GUI, this machine being a headless server hosting the Arduino for purposes of home automation. At one time, prior to breakage (suspected from package updates), I was using Arduino-Makefile (GitHub - sudar/Arduino-Makefile: Makefile for Arduino sketches. It defines the workflows for compiling code, flashing it to Arduino and even communicating through Serial.), but that project under the present state of the packages now evidently has irreconcilable path/environment problems in my configuration. In my efforts to regain my system's ability to up/download arduino sketches, I'm hoping to get success by switching from Arduino-Makefile to Arduino-builder (GitHub - arduino/arduino-builder: A command line tool for compiling Arduino sketches). Arduino-builder success has been hampered by the error msg shown above. I've already tried to get past this error msg by placing links in various directories for both the device-specs directory as well as the .a files associated with the spec files.
System:
Ubuntu 1604 CLI (no gui, but in hopes of getting past this error I did install Arduino IDE 1.8.5 from https://github.com/arduino/Arduino/releases/download/1.8.5/Arduino-1.8.5.tar.xz)
Arduino-builder was installed using the "go" script for that purpose.
Any thoughts from you Linux CLI users? Thank you!