Update documentation to add an auto-generated list of packages.

lib/spack/docs/Makefile

@@ -21,6 +21,12 @@ I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
 
 all: html
 
+#
+# This autogenerates a package list.
+#
+package_list:
+	spack info -r > package_list.rst
+
 #
 # This creates a git repository and commits generated html docs.
 # It them pushes the new branch into THIS repository as gh-pages.
@@ -69,9 +75,10 @@ help:
 	@echo "  doctest    to run all doctests embedded in the documentation (if enabled)"
 
 clean:
+	-rm -f package_list.rst
 	-rm -rf $(BUILDDIR)/* $(APIDOC_FILES)
 
-html: apidoc
+html: apidoc package_list
 	$(SPHINXBUILD) -b html $(ALLSPHINXOPTS) $(BUILDDIR)/html
 	@echo
 	@echo "Build finished. The HTML pages are in $(BUILDDIR)/html."