update jinja2 to get better python3 support
the trailing newline hack is no longer necessary with a new jinja
python3 fix

based on a patch by Luca Barbato <lu_zero@gentoo.org>
Fix behaviour of dump_node_vcgattr_hook accroding to documentation
use gnu alloca builtin or malloc.h on windows

This should make the system to find/use alloca more robust.
fp-vrp: mark newly created nodes as visited to avoid visiting them again

The newly created nodes have no bitinfo so if we visiting them results
in a crash.

This should fix opt/fehler220.c