more build system cleaning and patch for bad include in Eigen

bootstrap.sh

@@ -3,7 +3,12 @@
 EIGEN_URL='http://bitbucket.org/eigen/eigen/get/3.3.5.tar.bz2'
 
 echo "-- deploying Eigen source..."
-wget ${EIGEN_URL} --no-check-certificate && ./scripts/update_eigen.sh `basename ${EIGEN_URL}` && rm `basename ${EIGEN_URL}`
+ARC=`basename ${EIGEN_URL}`
+wget ${EIGEN_URL} --no-check-certificate && ./scripts/update_eigen.sh ${ARC} && rm ${ARC}
+# patch for non-portable includes in Eigen 3.3.5
+# apparently already fixed in Eigen HEAD so it should not be 
+# a problem in the future (A.P.)
+patch Grid/Eigen/unsupported/CXX11/Tensor scripts/eigen-3.3.5.Tensor.patch
 
 echo '-- generating Make.inc files...'
 ./scripts/filelist

scripts/eigen-3.3.5.Tensor.patch

@@ -0,0 +1,19 @@
+--- ./Eigen/unsupported/Eigen/CXX11/Tensor	2018-07-23 10:33:42.000000000 +0100
++++ Tensor	2018-08-28 16:15:56.000000000 +0100
+@@ -25,7 +25,7 @@
+ #include <utility>
+ #endif
+ 
+-#include <Eigen/src/Core/util/DisableStupidWarnings.h>
++#include "../../../Eigen/src/Core/util/DisableStupidWarnings.h"
+ 
+ #include "../SpecialFunctions"
+ #include "src/util/CXX11Meta.h"
+@@ -147,6 +147,6 @@
+ 
+ #include "src/Tensor/TensorIO.h"
+ 
+-#include <Eigen/src/Core/util/ReenableStupidWarnings.h>
++#include "../../../Eigen/src/Core/util/ReenableStupidWarnings.h"
+ 
+ //#endif // EIGEN_CXX11_TENSOR_MODULE