Fix autoreconf on Debian

For some reason, Automake doesn't search the current directory correctly when
searching for helper scripts, when 'nut' is running as a git-submodule, as it is
the case with the website repository

configure.ac

@@ -4,6 +4,7 @@ dnl +------------------------------------------------------------------+
 
 dnl NUT version number is defined here, with a Git suffix in include/nut_version.h
 AC_INIT(nut, 2.7.4, [https://github.com/networkupstools/nut/issues])
+AC_CONFIG_AUX_DIR([.])
 AC_CONFIG_SRCDIR(server/upsd.c)
 AC_CONFIG_MACRO_DIR([m4])
 echo "Network UPS Tools version ${PACKAGE_VERSION}"