+dnl Work around a bug in m4_expand that broke AT_SETUP in autoconf 2.62,
+dnl by using the definition from 2.63.
+m4_version_prereq([2.63], [],
+[m4_define([m4_expand], [_$0(-=<{($1)}>=-)])
+m4_define([_m4_expand],
+[m4_changequote([-=<{(], [)}>=-])$1m4_changequote([, ])])])