Switch to ISL 0.16.1

[Richard Biener]

Hi,

the following patch switches download_prerequesites to use ISL 0.16.1
(just put that into infrastructure/).

I've verified it works for me (on the gcc-5 branch and trunk).

Ok?

Thanks,
Richard.

Index: contrib/download_prerequisites
===================================================================
--- contrib/download_prerequisites      (revision 233418)
+++ contrib/download_prerequisites      (working copy)
@@ -48,7 +48,7 @@ ln -sf $MPC mpc || exit 1
 
 # Necessary to build GCC with the Graphite loop optimizations.
 if [ "$GRAPHITE_LOOP_OPT" = "yes" ] ; then
-  ISL=isl-0.15
+  ISL=isl-0.16.1
 
   wget ftp://gcc.gnu.org/pub/gcc/infrastructure/$ISL.tar.bz2 || exit 1
   tar xjf $ISL.tar.bz2  || exit 1