autogen.sh: create config/autoconf and config/m4

...old autoconf fails without it.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
diff --git a/autogen.sh b/autogen.sh
index 29db9c9..737d646 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
 
+set -e
+
 #
 # usage:
 #
@@ -17,6 +19,7 @@
 
 banner "autoreconf"
 
+mkdir -p config/autoconf config/m4
 autoreconf --force --install --symlink -Wall || exit $?
 
 banner "Finished"