Issue #15494: Install new test/support directory.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 0009802..73988b2 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -1012,7 +1012,7 @@
tkinter/test/test_ttk site-packages test \
test/capath test/data \
test/cjkencodings test/decimaltestdata test/xmltestdata \
- test/subprocessdata test/sndhdrdata \
+ test/subprocessdata test/sndhdrdata test/support \
test/tracedmodules test/encoded_modules \
test/namespace_pkgs \
test/namespace_pkgs/both_portions \