Silence warnings on CMP0026 with CMake 3.x

(cherry picked from commit 0d5ca8bebb)

modules/TDEMacros.cmake

@@ -107,6 +107,17 @@ endif( )
 ########### slave part ends here ###############
 
 
+################################################
+#####
+##### CMP0026 states we should not read the LOCATION property of a target,
+##### and should be using generators instead. We can't do that here however
+##### because we need the value of the property at configure time.
+
+if( POLICY CMP0026 )
+  cmake_policy( SET CMP0026 OLD )
+endif( POLICY CMP0026 )
+
+
 ################################################
 #####
 ##### tde_install_icons( <icons...> THEME <svgicons> DESTINATION <destdir> )