feat(3p/lisp/closure-html): init at 2017-04-19

This one requires a bit of jumping through hoops. Patching the dtd /
catalog lookup is quite straightforward and similar to cxml, but the
CLOSURE-HTML:*html-dtd* variable gives us a bit of trouble: It is
defined quite late in `html-parser.lisp`, but files that need to be
built first already reference it. SBCL has apparently decided to be
particular about this and emits a `WARNING` (!) condition for this
which is also worthy of `failure-p` of `compile-file` being true,
so that `buildLisp` will abort compilation. We workaround this issue
by injecting an extra source file which `defvar`s the desired symbol.

A similar issue exists with `dump-dtd` which references
`CL-USER:*HTML-DTD*` for some reason. Since this is a helper intended
for development (?) and not exported we just throw it away via a
patch.

Change-Id: Ic0f92815a21f3793925c49a70a72f4a86791efe4
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3263
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>

third_party/lisp/closure-html/dtds-from-store.patch

@@ -0,0 +1,16 @@
+diff --git a/src/parse/html-parser.lisp b/src/parse/html-parser.lisp
+index 4e45b81..5025a26 100644
+--- a/src/parse/html-parser.lisp
++++ b/src/parse/html-parser.lisp
+@@ -36,10 +36,7 @@
+         (make-pathname
+ 	 :name nil
+ 	 :type nil
+-	 :defaults (merge-pathnames
+-		    "resources/"
+-		    (asdf:component-relative-pathname
+-		     (asdf:find-system :closure-html))))))
++	 :defaults "@out@/resources/")))
+     (loop
+        :for (name . filename)
+        :in '(("-//W3O//DTD W3 HTML 3.0//EN" . "dtd/HTML-3.0")