+#serial 11
+
+# Define m4_ifblank and m4_ifnblank macros from introduced in
+# autotools 2.64 m4sugar.m4 if using an earlier autotools.
+
+ifdef([m4_ifblank], [], [
+m4_define([m4_ifblank],
+[m4_if(m4_translit([[$1]], [ ][ ][
+]), [], [$2], [$3])])
+])
+
+
+ifdef([m4_ifnblank], [], [
+m4_define([m4_ifnblank],
+[m4_if(m4_translit([[$1]], [ ][ ][
+]), [], [$3], [$2])])
+])