Description of problem:
Restraint build is failing in the following environment:
Restraint - 0.1.38
GLib - 2.56.1
Automake
GCC 9

Version-Release number of selected component (if applicable):
0.1.38

How reproducible:
Try to build restraint on Fedora Rawhide (Rawhide will be F30 in the future)

Actual results:
Build failed on GLib
  CC       libgio_2_0_la-gdbusauth.lo
gdbusauth.c: In function '_g_dbus_auth_run_server':
gdbusauth.c:1302:11: error: '%s' directive argument is null [-Werror=format-overflow=]
 1302 |           debug_print ("SERVER: WaitingForBegin, read '%s'", line);

Expected results:
Restraint build is successful

Additional info: