-m4_if(m4_PACKAGE_VERSION, [2.61],,
-[m4_fatal([this file was generated for autoconf 2.61.
-You have another version of autoconf. If you want to use that,
-you should regenerate the build system entirely.], [63])])
+m4_ifndef([AC_AUTOCONF_VERSION],
+ [m4_copy([m4_PACKAGE_VERSION], [AC_AUTOCONF_VERSION])])dnl
+m4_if(AC_AUTOCONF_VERSION, [2.63],,
+[m4_warning([this file was generated for autoconf 2.63.
+You have another version of autoconf. It may work, but is not guaranteed to.
+If you have problems, you may need to regenerate the build system entirely.
+To do so, use the procedure documented by the package, typically `autoreconf'.])])