GNU Autoconf 2.70 is out. “Noteworthy changes include support for the
2011 revisions of the C and C++ standards, support for reproducible
builds, improved support for cross-compilation, improved compatibility
with current compilers and shell utilities, more efficient generated
shell code, and many bug fixes.” See this article for more information on what has
been happening with Autoconf.

Source: LWN.net – GNU autoconf-2.70 released