(Win) 7zip notice in README; fix cmake 3.x warning

README.md

@@ -12,7 +12,8 @@ The goal is using one single CMake code to build against *SuiteSparse* in standa
   * (1) Install [CMake](http://www.cmake.org/).
   * (2) Only for Linux/Mac: Install LAPACK & BLAS. In Debian/Ubuntu: `sudo apt-get install liblapack-dev libblas-dev`
   * (3) Clone or download this project ([latest release](https://github.com/jlblancoc/suitesparse-metis-for-windows/releases)) and extract it somewhere in your disk, say `SP_ROOT`.
-      * (Optional: CMake script will download the following code for you if not found) 
+      * In Windows, install [7-Zip](http://www.7-zip.org/) if you want CMake to download SuiteSparse sources automatically for you. 
+	  * (OPTIONAL) Otherwise, manually install SuiteSparse as follows: 
         * Populate the directories within `SP_ROOT` with the original sources from each project:
           * *`SuiteSparse`:* 
             * Download [SuiteSparse-X.Y.Z.tar.gz](http://www.cise.ufl.edu/research/sparse/SuiteSparse/) from Tim Davis' webpage. 

checkGetSuiteSparse.cmake

@@ -12,6 +12,10 @@
 ## Created by jesnault (jerome.esnault@inria.fr) 2014-01-21
 ## Updated by jesnault (jerome.esnault@inria.fr) 2014-01-21
 
+if(POLICY CMP0053)
+	cmake_policy(SET CMP0053 OLD) # To correctly interpret the 7-zip strings below
+endif()
+
 ## try first with 7-Zip, and with standard cmake tar command otherwise
 macro(SuiteSparse_unzip whichZipFile)
 	find_program(7ZIP_CMD NAMES 7z DOC "7-zip executable"