bpo-40683: Add zoneinfo to LIBSUBDIRS (GH-20229)

Without this, only the _zoneinfo module is getting installed, not the
zoneinfo module. I believe this was not noticed earlier because
test.test_zoneinfo was also not being installed.
(cherry picked from commit 2abeded)

Co-authored-by: Paul Ganssle <[email protected]>

Author: miss-islington

Makefile.pre.in

@@ -1429,6 +1429,7 @@ LIBSUBDIRS=	tkinter tkinter/test tkinter/test/test_tkinter \
 		test/test_importlib/source \
 		test/test_importlib/zipdata01 \
 		test/test_importlib/zipdata02 \
+		test/test_zoneinfo test/test_zoneinfo/data \
 		test/ziptestdata \
 		asyncio \
 		test/test_asyncio \
@@ -1450,7 +1451,8 @@ LIBSUBDIRS=	tkinter tkinter/test tkinter/test/test_tkinter \
 		multiprocessing multiprocessing/dummy \
 		unittest unittest/test unittest/test/testmock \
 		venv venv/scripts venv/scripts/common venv/scripts/posix \
-		curses pydoc_data
+		curses pydoc_data \
+		zoneinfo
 libinstall:	build_all $(srcdir)/Modules/xxmodule.c
 	@for i in $(SCRIPTDIR) $(LIBDEST); \
 	do \

Misc/NEWS.d/next/Build/2020-05-19-10-54-08.bpo-40683.W8JHrr.rst

@@ -0,0 +1,2 @@
+Fixed an issue where the :mod:`zoneinfo` module and its tests were not
+included when Python is installed with ``make``.