Delete backup and lock-files in distdir

Makefile.am

@@ -103,8 +103,12 @@ dist-hook:
 	rm -rf `find $(distdir) -name .svn -a -type d`
 	@echo Deleting CVS directories in $(distdir)
 	rm -rf `find $(distdir) -name CVS`
-	@echo Deleting .cvsignore file in $(distdir)
+	@echo Deleting .cvsignore files in $(distdir)
 	rm -f `find $(distdir) -name '.cvsignore'`
+	@echo Deleting backup files in $(distdir)
+	rm -f `find $(distdir) -name '*~'`
+	@echo Deleting stale lock-files in $(distdir)
+	rm -f `find $(distdir) -name '.#*'`
 
 #
 # NOTE: you better have GRAPE installed properly before doing this.