On Fedora Core 26, GCC 7.1.1, configured with --enable-developer

making all in /home/ray/src/bind9/lib/isc/tests
make[3]: Entering directory '/home/ray/src/bind9/lib/isc/tests'
...
gcc  -I/home/ray/src/bind9 -I../../.. -I. -Iinclude
-I/home/ray/src/bind9/lib/isc/include -I../../../lib/isc
-I../../../lib/isc/include -I../../../lib/isc/unix/include
-I../../../lib/isc/pthreads/include -I../../../lib/isc/x86_32/
ht_test.c: In function ‘atfu_isc_ht_iterator_body’:
ht_test.c:184:49: error: ‘ key of a raw hashtable!!’ directive output
truncated writing 25 bytes into a region of size between 11 and 15
[-Werror=format-truncation=]
   snprintf((char *)key, 16, "%lld key of a raw hashtable!!", i);
                                  ~~~~~~~~~~~~~~~^~~~~~~~~~

and then several more very similar errors before the compile craps out.