+# Calculate sha256sum of any plain file within a given directory
+# $(1) => Input directory
+define sha256sums
+ (cd $(1); find . -maxdepth 1 -type f -not -name 'sha256sums' -printf "%P\n" | sort | \
+ xargs openssl dgst -sha256 | sed -ne 's!^SHA256(\(.*\))= \(.*\)$$!\2 *\1!p' > sha256sums)
+endef
+