update udev rules dir location again

Instead of hardcoding whatever the new fashion is every few months, which might
even differ between distributions, just put the rules where udev says we should.

https://bugs.freedesktop.org/show_bug.cgi?id=50426

configure.ac

@@ -129,6 +129,8 @@ AC_SUBST(GLIB_LIBS)
 imagemagick_found=no
 gdkpixbuf_found=no
 
+AC_SUBST([udev_rulesdir], [$($PKG_CONFIG --variable=udevdir udev)/rules.d])
+
 if test "$require_imaging" = "yes"; then
 	PKG_CHECK_MODULES(IMAGING, gthread-2.0 gdk-pixbuf-2.0, [gdkpixbuf_found=yes], [gdkpixbuf_found=no])
 	if test "$gdkpixbuf_found" != "yes"; then

libfprint/Makefile.am

@@ -79,7 +79,6 @@ fprint_list_udev_rules_CFLAGS = -fvisibility=hidden -I$(srcdir)/nbis/include $(L
 fprint_list_udev_rules_LDADD = $(builddir)/libfprint.la
 
 udev_rules_DATA = 60-fprint-autosuspend.rules
-udev_rulesdir = $(libdir)/udev/rules.d/
 
 $(udev_rules_DATA): fprint-list-udev-rules
 	$(builddir)/fprint-list-udev-rules > $@