patch 8.0.0522: Win32: when 'clipboard' is "unnamed" yyp does not work

Problem:    MS-Windows: when 'clipboard' is "unnamed" yyp does not work in a
            :global command.
Solution:   When setting the clipboard was postponed, do not clear the
            register.
diff --git a/src/Makefile b/src/Makefile
index e8314ea..82da653 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -2145,6 +2145,7 @@
 	test_ga \
 	test_gf \
 	test_glob2regpat \
+	test_global \
 	test_gn \
 	test_goto \
 	test_gui \