Actually the exit; does nothing but throw this warning.
...\arduino_modified_sketch_800891\sketch_may17b.ino: In function 'void setup()':
C:\Users\DaD\AppData\Local\Temp\arduino_modified_sketch_800891\sketch_may17b.ino:9:11: warning: statement is a reference, not call, to function ‘exit’ [-Waddress]
…\arduino_modified_sketch_800891\sketch_may17b.ino:9:11: warning: statement has no effect [-Wunused-value]
The exit(0) function would exit loop, disable interrupts and freeze.
That code is in loop(), not in setup(). Why does the compiler think it is in setup()?
I installed the Adafruit PWM Servo library (against my better judgement) and do not get any errors:
Build options changed, rebuilding all Sketch uses 9122 bytes (3%) of program storage space. Maximum is 253952 bytes. Global variables use 659 bytes (8%) of dynamic memory, leaving 7533 bytes for local variables. Maximum is 8192 bytes.