patch 7.4.1450
Problem:    Json encoding still fails when encoding is not utf-8.
Solution:   Set 'encoding' before :scriptencoding.  Run the json test
            separately to avoid affecting other tests.
diff --git a/src/testdir/Make_all.mak b/src/testdir/Make_all.mak
index 510b743..8901b15 100644
--- a/src/testdir/Make_all.mak
+++ b/src/testdir/Make_all.mak
@@ -176,6 +176,7 @@
 	    test_channel.res \
 	    test_hardcopy.res \
 	    test_increment.res \
+	    test_json.res \
 	    test_langmap.res \
 	    test_perl.res \
 	    test_quickfix.res \