Allow buildbot to pass extra test flags to regrtest (specifically -r) via the environment.
diff --git a/Makefile.pre.in b/Makefile.pre.in
index 1cc43e6..bb1aeea 100644
--- a/Makefile.pre.in
+++ b/Makefile.pre.in
@@ -550,7 +550,7 @@
 # generated bytecode.  This is sometimes a very shy bug needing a lot of
 # sample data.
 
-TESTOPTS=	-l
+TESTOPTS=	-l $(EXTRATESTOPTS)
 TESTPROG=	$(srcdir)/Lib/test/regrtest.py
 TESTPYTHON=	$(RUNSHARED) ./$(BUILDPYTHON) -E -tt
 test:		all platform