For afl target, don't build tests.

Author: jgm

Diff for: Makefile

@@ -73,7 +73,7 @@ prof:
 afl:
 	@[ -n "$(AFL_PATH)" ] || { echo '$$AFL_PATH not set'; false; }
 	mkdir -p $(BUILDDIR)
-	cd $(BUILDDIR) && cmake .. -DCMAKE_C_COMPILER=$(AFL_PATH)/afl-clang
+	cd $(BUILDDIR) && cmake .. -DCMARK_TESTS=0 -DCMAKE_C_COMPILER=$(AFL_PATH)/afl-clang
 	$(MAKE)
 	$(AFL_PATH)/afl-fuzz \
 	    -i test/afl_test_cases \