Improve GIOModule test coverage

Add a dedicated test for GIOModule.

gio/tests/modules/Makefile.am

@@ -0,0 +1,27 @@
+NULL =
+
+LDADD = \
+	$(top_builddir)/gio/libgio-2.0.la               \
+	$(top_builddir)/gobject/libgobject-2.0.la       \
+	$(top_builddir)/gmodule/libgmodule-2.0.la       \
+	$(top_builddir)/glib/libglib-2.0.la             \
+	$(NULL)
+
+
+AM_CPPFLAGS = \
+	$(gio_INCLUDES) $(GLIB_DEBUG_FLAGS) 		\
+	-I$(top_builddir)/gio 				\
+	-I$(top_srcdir)/gio
+
+testmoduledir = $(installed_testdir)/modules
+testmodule_LTLIBRARIES = \
+	libtestmodulea.la \
+	libtestmoduleb.la
+
+libtestmodulea_la_SOURCES = test-module-a.c
+libtestmodulea_la_LIBADD = $(LDADD)
+libtestmodulea_la_LDFLAGS = $(LDFLAGS) -no-undefined -avoid-version
+
+libtestmoduleb_la_SOURCES = test-module-b.c
+libtestmoduleb_la_LIBADD = $(LDADD)
+libtestmoduleb_la_LDFLAGS =$(LDFLAGS) -no-undefined -avoid-version