Arduino: 1.8.9 (Windows 7), Board: "Arduino/Genuino Mega or Mega 2560, ATmega2560 (Mega 2560)"
ECDSA_test2:28:20: error: common.h: No such file or directory
exit status 1
common.h: No such file or directory
This report would have more information with
"Show verbose output during compilation"
option enabled in File -> Preferences.