patch 8.0.0537: illegal memory access with :z and large count

Problem:    Illegal memory access with :z and large count.
Solution:   Check for number overflow, using long instead of int. (Dominique
            Pelle, closes #1612)
diff --git a/src/Makefile b/src/Makefile
index 82da653..5ceae2f 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2122,10 +2122,10 @@
 	test_delete \
 	test_diffmode \
 	test_digraph \
-	test_functions \
 	test_display \
 	test_edit \
 	test_ex_undo \
+	test_ex_z \
 	test_execute_func \
 	test_expand \
 	test_expand_dllpath \
@@ -2142,6 +2142,7 @@
 	test_fnameescape \
 	test_fnamemodify \
 	test_fold \
+	test_functions \
 	test_ga \
 	test_gf \
 	test_glob2regpat \