Add link checker builder, written for GHOP by Thomas Lamb.

Doc/Makefile

@@ -16,11 +16,12 @@ ALLSPHINXOPTS = -b $(BUILDER) -d build/doctrees -D latex_paper_size=$(PAPER) \
 
 help:
 	@echo "Please use \`make <target>' where <target> is one of"
-	@echo "  html     to make standalone HTML files"
-	@echo "  web      to make file usable by Sphinx.web"
-	@echo "  htmlhelp to make HTML files and a HTML help project"
-	@echo "  latex    to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
-	@echo "  changes  to make an overview over all changed/added/deprecated items"
+	@echo "  html      to make standalone HTML files"
+	@echo "  web       to make file usable by Sphinx.web"
+	@echo "  htmlhelp  to make HTML files and a HTML help project"
+	@echo "  latex     to make LaTeX files, you can set PAPER=a4 or PAPER=letter"
+	@echo "  changes   to make an overview over all changed/added/deprecated items"
+	@echo "  linkcheck to check all external links for integrity"
 
 checkout:
 	@if [ ! -d tools/sphinx ]; then \
@@ -71,6 +72,11 @@ changes: BUILDER = changes
 changes: build
 	@echo "The overview file is in build/changes."
 
+linkcheck: BUILDER = linkcheck
+linkcheck: build
+	@echo "Link check complete; look for any errors in the above or in" \
+	      "build/$(BUILDER)/output.txt"
+
 clean:
 	-rm -rf build/*
 	-rm -rf tools/sphinx

Doc/README.txt

@@ -50,6 +50,10 @@ Available make targets are:
 
  * "latex", which builds LaTeX source files that can be run with "pdflatex"
    to produce PDF documents.
+ 
+ * "linkcheck", which checks all external references to see whether they are
+   broken, redirected or malformed, and outputs this information to stdout
+   as well as a plain-text (.txt) file.
 
  * "changes", which builds an overview over all versionadded/versionchanged/
    deprecated items in the current version. This is meant as a help for the