Ensure an image-missing icon is available

It is bad if the image that is used as a fallback for missing
images goes missing itself, so include it as a resource. This
way, it will always be available.

gtk/Makefile.am

@@ -1405,10 +1405,14 @@ gtk.gresource.xml: Makefile.am
 	  n=`basename $$f`; \
 	  echo -e "    <file compressed=\"true\">ui/$$n</file>" >> $@; \
 	done; \
-	for s in 16x16 22x22 24x24 32x32; do \
-	  for f in $(srcdir)/resources/icons/$$s/actions/*.png; do \
-	    n=`basename $$f`; \
-	    echo -e "    <file>icons/$$s/actions/$$n</file>" >> $@; \
+	for c in actions status; do \
+	  for s in 16x16 22x22 24x24 32x32 48x48; do \
+	    if test -d $(srcdir)/resources/icons/$$s/$$c; then \
+	      for f in $(srcdir)/resources/icons/$$s/$$c/*.png; do \
+	        n=`basename $$f`; \
+	        echo -e "    <file>icons/$$s/$$c/$$n</file>" >> $@; \
+	      done; \
+	    fi; \
 	  done; \
 	done; \
 	echo -e "  </gresource>" >> $@; \