named-checkzone hangs when compiled with afl-clang-fast

One of the fuzzing tests carried out is to fuzz named-checkzone. To do this, BIND is built with aft-clang-fast using the "configure" command:

AFL_HARDEN=1 CFLAGS=afl-clang-fast ./configure

When built with the code in commit 1c57b73e (oss-fuzz: Improve interaction with fuzzing tools and add new tests in fuzz/ directory) named-checkconf hangs when run on a simple zone file. It runs correctly when BIND is built with the code in the previous commit (d30b90db Merge branch '484-fix-non-libtool-build' into 'master').

This occurs on Debian 9 with AFL 2.52b. (The hang also occurs with the latest version of master on Fedora 27.) FWIW, the zone file used contained:

$TTL 300
@ 			IN SOA	marka.isc.org. ns.server. (
				2010   	; serial
				600         	; refresh
				600         	; retry
				1200    	; expire
				600       	; minimum
				)
@			NS	ns
ns			A	10.53.0.5
foo			TXT	"From NS 5"
bar			TXT	"From NS 5"