Align gtkmm test suite with recent template updates

This is not used by default for gnucash, and maybe even
not used at all. At least it's consistent with the other
test files now.

src/optional/gtkmm/test/Makefile.am

@@ -8,17 +8,25 @@ include $(top_srcdir)/test-templates/Makefile.decl
 #after $(top_srcdir) or $(top_builddir):
 MODULEPATH = src/optional/gtkmm
 
+#The test program. You'll need to add to this if you have more than one module above.
+
+check_PROGRAMS = test-gtkmm
+
+TESTS = ${check_PROGRAMS}
+
+test_gtkmmdir = ${top_srcdir}/${MODULEPATH}/test
+
+#Program files for tests go here. It's probably best to have one for
+#each file in the parent directory. Include
+#test_foo_support.c if you have one and aren't building the
+#support library.
 test_gtkmm_SOURCES = \
 	test-gtkmm.cpp \
 	test-book.cpp
 
-test_gtkmm_HEADERSS = \
+test_gtkmm_HEADERS = \
 	$(top_srcdir)/${MODULEPATH}/gncmm/Book.hpp
 
-TEST_PROGS += test-gtkmm
-
-noinst_PROGRAMS = ${TEST_PROGS}
-
 #The tests might require more libraries, but try to keep them
 #as independent as possible.
 test_gtkmm_LDADD = ${top_builddir}/${MODULEPATH}/libgncmod-gtkmm.la \