autogen.sh: make autoreconf use automake-1.11 when available
autogen.sh: make autoreconf use automake-1.11 when available

This patch exports $ACLOCAL and $AUTOMAKE, otherwise autoreconf
may use an older version instead.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>

http://bugzilla.clutter-project.org/show_bug.cgi?id=2504

djdeath/clutter-android,heysion/clutter-clone,dlespiau/clutter,collects/clutter,ebassi/clutter,kerrickstaley/clutter-vala,djdeath/clutter-multithreaded,Distrotech/clutter,GNOME/clutter,kerrickstaley/clutter-vala,spatulasnout/clutter,dlespiau/clutter,ebassi/clutter,jigpu/clutter,collects/clutter,GNOME/clutter,djdeath/clutter,jigpu/clutter,jigpu/clutter,collects/clutter,Distrotech/clutter,nobled/clutter,jigpu/clutter,heysion/clutter-clone,djdeath/clutter,djdeath/clutter,djdeath/clutter,Distrotech/clutter,djdeath/clutter-android,djdeath/clutter-android,ebassi/clutter,kerrickstaley/clutter-vala,kerrickstaley/clutter-vala,djdeath/clutter-android,djdeath/clutter-multithreaded,dlespiau/clutter,ebassi/clutter,Distrotech/clutter,collects/clutter,Distrotech/clutter,djdeath/clutter-android,collects/clutter,heysion/clutter-clone,ebassi/clutter,djdeath/clutter,djdeath/clutter-multithreaded,Distrotech/clutter,djdeath/clutter,GNOME/clutter,spatulasnout/clutter,spatulasnout/clutter,spatulasnout/clutter,nobled/clutter,jigpu/clutter,djdeath/clutter-multithreaded,heysion/clutter-clone,GNOME/clutter,nobled/clutter,GNOME/clutter,spatulasnout/clutter,jigpu/clutter,heysion/clutter-clone