Add support for cold plugging devices, auto-loading of modules

This patch adds a new plugin to Finit called modprobe.  It probes in
/sys/devices after modalias files and then calls 'modprobe -ab' for
each alias listed.

For hot-plugging we recommend adding the following to /etc/mdev.conf

  $MODALIAS=.*	root:root	0660	@modprobe -b "$MODALIAS"

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

plugins/Makefile.am

@@ -7,7 +7,7 @@ AM_CPPFLAGS        += $(lite_CFLAGS)
 
 if STATIC
 noinst_LTLIBRARIES  = libplug.la
-libplug_la_SOURCES  = bootmisc.c rtc.c initctl.c pidfile.c procps.c tty.c urandom.c
+libplug_la_SOURCES  = bootmisc.c modprobe.c rtc.c initctl.c pidfile.c procps.c tty.c urandom.c
 
 if BUILD_ALSA_UTILS_PLUGIN
 libplug_la_SOURCES += alsa-utils.c
@@ -52,7 +52,7 @@ libplug_la_SOURCES += resolvconf.c
 endif
 
 else
-pkglib_LTLIBRARIES  = bootmisc.la rtc.la initctl.la pidfile.la procps.la tty.la urandom.la
+pkglib_LTLIBRARIES  = bootmisc.la modprobe.la rtc.la initctl.la pidfile.la procps.la tty.la urandom.la
 
 if BUILD_ALSA_UTILS_PLUGIN
 pkglib_LTLIBRARIES += alsa-utils.la