first working version for the new build system

scripts/update_eigen.sh

@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+if (( $# != 1 )); then
+    echo "usage: `basename $0` <archive>" 1>&2
+    exit 1
+fi
+ARC=$1
+
+INITDIR=`pwd`
+rm -rf lib/Eigen
+ARCDIR=`tar -tf ${ARC} | head -n1 | sed -e 's@/.*@@'`
+tar -xf ${ARC}
+cd ${ARCDIR}
+(tar -cf - Eigen --exclude='*.txt' 2>/dev/null) | tar -xf - -C ../lib/
+cd ../lib
+echo 'eigen_files =\' > Eigen.inc
+find Eigen -type f -print | sed 's/^/  /;$q;s/$/ \\/' >> Eigen.inc
+cd ${INITDIR}
+rm -rf ${ARCDIR}