installing glade3 interface file with autotools

[Mick]

I'm trying to rebuild my application using the current(ish) glade and
autoconf/automake and have been having a nightmare trying to get the
XML file created from glade by: 
gtk-builder-convert nuchimp.glade nuchimp.xml

After reading various documents I have the following Makefile.am:
bin_PROGRAMS = nuchimp

nuchimp_SOURCES = \
        callback.c callback.h \
        chimp.c chimp.h \
        main.c main.h \
        parsecfg.c parsecfg.h

xmldir = $(datadir)
xml_DATA = nuchimp.xml

AM_CPPFLAGS = $(GTK_CFLAGS)
AM_LDFLAGS = $(GTK_LIBS) -export-dynamic

the clearest doc stated the two lines beginning xml would do exactly
what I need but I make, I get:
make[2]: *** No rule to make target `nuchimp.xml', needed by `all-am'.
Stop.

this is doing my head in so PLEASE, someone wiser than me, point me to a
clear explanation of the process.