Use install_file function rather than direct cp, since it lets us use

INSTALL_PREFIX

scripts/build.files.none/build.install-files

@@ -4,11 +4,11 @@
 echo "Installing files into ${FILESDIR}"
 build_dir_tree "${FILESDIR}" || return 1
 
-# copy across the Doxygen-generated documentation
+# copy across the files (note this copies everything with mode 0644).
 for file in src/@NAME@/*
 do
     [ "$(echo $(basename ${file}) | cut -b1-6)" == "build." ] && continue
-    do_cmd cp -a ${file} ${FILESDIR} || return 1
+    install_file ${file} ${FILESDIR} 0644 || return 1
 done
 
 print_success "Files installed"