Add licheck build instructions for Coin builds

 132         exe_dir = optionDict['WORK_DIR'] + '/license-managing/licheck'
 134         if optionDict['TARGET_ENV'].lower().startswith("win"):
 135             cmd_args = [r'c:\Utils\jom\jom.exe', '-f', 'Makefile_win']
 136             do_execute_sub_process(cmd_args, exe_dir, True)  # produces licheck.exe
 139         elif optionDict['TARGET_ENV'].lower().startswith("linux"):
 140             cmd_args = ['make', '-j6', '-f', 'Makefile_unix']
 141             do_execute_sub_process(cmd_args, exe_dir, True)  # produces licheck -> rename as licheck64
 145         else:
 146             cmd_args = ['make', '-j6', '-f', 'Makefile_macos']
 147             do_execute_sub_process(cmd_args, exe_dir, True)  # produces licheck -> rename as licheck_mac