While gdbm 1.16 builds fine on macOS 10.13.5, gdbm 1.17 does not. It fails with the following error:

libtool: compile: clang -DHAVE_CONFIG_H -I. -I.. -DIN_GDBM -DLOCALEDIR=\"/usr/local/Cellar/gdbm/1.17/share/locale\" -g -O2 -c gdbmstore.c -o gdbmstore.o >/dev/null 2>&1
gdbmsync.c:31:3: error: non-void function 'gdbm_sync' should return a value [-Wreturn-type]
GDBM_ASSERT_CONSISTENCY (dbf, );
^
./gdbmdefs.h:278:4: note: expanded from macro 'GDBM_ASSERT_CONSISTENCY'
return onerr; \
^
1 error generated.
make[3]: *** [gdbmsync.lo] Error 1
make[3]: *** Waiting for unfinished jobs....
make[2]: *** [all] Error 2
make[1]: *** [all-recursive] Error 1
make: *** [all] Error 2

My configure flags are:
--disable-dependency-tracking
--disable-silent-rules
--without-readline"