The LANG vars aren't reset early enough so when sed tries to use [a-zA-Z] in 
option parsing, it may break.

http://bugs.gentoo.org/128253

--- configure
+++ configure
@@ -8,6 +8,19 @@
 #  New default: /usr/share/kbd
 #
 
+# NLS nuisances.
+for as_var in \
+  LANG LANGUAGE LC_ADDRESS LC_ALL LC_COLLATE LC_CTYPE LC_IDENTIFICATION \
+  LC_MEASUREMENT LC_MESSAGES LC_MONETARY LC_NAME LC_NUMERIC LC_PAPER \
+  LC_TELEPHONE LC_TIME
+do
+  if (set +x; test -z "`(eval $as_var=C; export $as_var) 2>&1`"); then
+    eval $as_var=C; export $as_var
+  else
+    unset $as_var
+  fi
+done
+
 prefix=
 datadir=
 mandir=