autogen.sh: run with set -e

If any autotool command fails, we want to abort, not keep running.
Otherwise, errors in say a Makefile.am will be missed as the automake
failure gets ignored and then lost in the noise.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

autogen.sh

 #! /bin/sh
 # Run this to generate all the initial makefiles, etc.
 
+set -e
+
 srcdir=`dirname $0`
 test -z "$srcdir" && srcdir=.