--- /root/autotools.eclass	2014-11-13 21:52:28.205593707 +0300
+++ /var/cache/portage/tree/eclass/autotools.eclass	2014-11-13 21:57:44.290191972 +0300
@@ -335,6 +335,8 @@ eautoconf() {
 		die "No configure.{ac,in} present!"
 	fi
 
+	rm -rf autom4te.cache || die
+
 	autotools_run_tool --at-m4flags autoconf "$@"
 }