Patch #735613: Pass install-purelib to idleinstall.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 39f2917..3bb44a4 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -875,6 +875,7 @@
 	./$(BUILDPYTHON) $(srcdir)/Tools/idle/setup.py install \
 	--check-tkinter \
 	--prefix=$(prefix) \
+	--install-purelib=$(LIBDEST) \
 	--install-scripts=$(BINDIR) \
 	--install-platlib=$(DESTSHARED) \
 	--root=/$(DESTDIR)