Remove @webchecker.pickle in the "clean" target.
diff --git a/Doc/Makefile b/Doc/Makefile
index 705d03a..fcac619 100644
--- a/Doc/Makefile
+++ b/Doc/Makefile
@@ -309,7 +309,7 @@
# - useful results: .dvi, .pdf, .ps, .texi, .info
clean:
rm -f @* *~ *.aux *.idx *.ilg *.ind *.log *.toc *.blg *.bbl *.py[co]
- rm -f *.bak *.orig lib1.texi *.out
+ rm -f *.bak *.orig lib1.texi *.out @webchecker.pickle
rm -f html-$(VERSION).tar.gz info-$(VERSION).tar.gz
rm -f pdf-$(VERSION).tar.gz postscript-$(VERSION).tar.gz
rm -f latex-$(VERSION).tar.gz