configure: Drop AM_MAINTAINER_MODE

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
autogen.sh: Honor NOCONFIGURE=1

See http://people.gnome.org/~walters/docs/build-api.txt

Signed-off-by: Alan Coopersmith <alan.coopersmith@oracle.com>
Fix abs() usage.

For long arguments, use labs().

Reviewed-by: Matt Turner <mattst88@gmail.com>
Signed-off-by: Thomas Klausner <wiz@NetBSD.org>