Set permissions with CMake

Rather than with Unix-specific chmod command.

Overlap/CMakeLists.txt

@@ -18,6 +18,8 @@ target_link_libraries(eddy_graph PRIVATE ezmpi Jumble::jumble
   Shapelib_03::shapelib_03 Contour_531::contour_531 gpc_f Geometry::geometry
   NR_util::nr_util MPI::MPI_Fortran)
 
-configure_file(eddy_graph.sh.in eddy_graph.sh @ONLY)
-execute_process(COMMAND chmod -w ${CMAKE_CURRENT_BINARY_DIR}/eddy_graph.sh)
+configure_file(eddy_graph.sh.in eddy_graph.sh @ONLY FILE_PERMISSIONS
+  OWNER_READ OWNER_EXECUTE GROUP_READ GROUP_EXECUTE WORLD_READ
+  WORLD_EXECUTE)
+
 include(Tests/CMakeLists.txt)