libinstall: For the first bytecode compilation pass, use -tt instead of

             -t.  This ensures that each installation from source is
             checked for compliance.  This is needed to make sure .py
             files in the various Lib/plat-foo/ directories are tested
             even if the core developers do not have access to the
             corresponding platforms.

Makefile.in

@@ -328,7 +328,7 @@ libinstall:	python $(srcdir)/Lib/$(PLATDIR)
 			done; \
 		done
 		PYTHONPATH=$(LIBDEST) \
-			./python$(EXE) -t $(LIBDEST)/compileall.py $(LIBDEST)
+			./python$(EXE) -tt $(LIBDEST)/compileall.py $(LIBDEST)
 		PYTHONPATH=$(LIBDEST) \
 			./python$(EXE) -O $(LIBDEST)/compileall.py $(LIBDEST)