gnu: Add boost@1.66.0.

* gnu/packages/boost.scm (boost-1.66): New public variable.

gnu/packages/boost.scm

@@ -110,6 +110,20 @@ across a broad spectrum of applications.")
     (license (license:x11-style "http://www.boost.org/LICENSE_1_0.txt"
                                 "Some components have other similar licences."))))
 
+(define-public boost-1.66
+  (package
+    (inherit boost)
+    (version "1.66.0")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "mirror://sourceforge/boost/boost/" version "/boost_"
+                    (string-map (lambda (x) (if (eq? x #\.) #\_ x)) version)
+                    ".tar.bz2"))
+              (sha256
+               (base32
+                "1aaw48cmimsskzgiclwn0iifp62a5iw9cbqrhfari876af1828ap"))))))
+
 (define-public mdds
   (package
     (name "mdds")