Blender Git Loki

Two fixes in renderpipe...

- Renderwin still used a thread-unsafe malloc, in the header text print

- Setting clipping flags in vertices for parts required a mutex lock after
all... I thought it would go fine, but noticed on renders with small
amounts of faces that sometimes faces disappear from a render.
(was doing movie credits, so all faces are visible! Otherwise it would
have hardly been noticable...)