If you don't mind me joining this thread, I would like your help on a similar issue.
I clicked on 'Libraries'->Add Library->Browse Libraries. Atmel sees the library project in the solution. All is good, the library shows up in the main project. By the way, I am NOT trying to include the Arduino libraries.
Unfortunately, I don't know how to call it in "main.c". I tried #include <ADC>, #include <ADC.h> (there is no .h file), #include <ADC.a> (there is a .a file), #include "ADC.h" and other variations. As you have guessed, none worked.
The Output gives this if there is no include:
implicit declaration of function 'initADC' [-Wimplicit-function-declaration]
And this for each flavor of #include I tried (#include <ADC> in that case):
recipe for target 'main.o' failed ArduinoRobot
ADC: No such file or directory ArduinoRobot
Did I miss any steps ? What am I doing wrong ?