gnu: Add hnsd.

Thank you, Handshake!

* gnu/packages/dns.scm (hnsd): New variable.

gnu/packages/dns.scm

@@ -58,6 +58,7 @@ (define-module (gnu packages dns)
   #:use-module ((guix licenses) #:prefix license:)
   #:use-module (guix packages)
   #:use-module (guix download)
+  #:use-module (guix git-download)
   #:use-module (guix utils)
   #:use-module (guix build-system gnu)
   #:use-module (guix build-system trivial))
@@ -727,3 +728,56 @@ (define-public ddclient
 record and alternative name management.  It caches the address, and only
 attempts the update when it has changed.")
     (license license:gpl2+)))
+
+(define-public hnsd
+  ;; There have been no releases yet, hence this commit.
+  (let ((revision "0")
+        (commit "895d89c25d316d18df9d374fe78aae3902bc89fb"))
+   (package
+     (name "hnsd")
+     (version (git-version "0.0" revision commit))
+     (source (origin
+               (method git-fetch)
+               (uri (git-reference
+                     (url "https://github.com/handshake-org/hnsd")
+                     (commit commit)))
+               (sha256
+                (base32
+                 "0704y73sddn24jga9csw4gxyfb3pnrfnk0vdcph84n1h38490l16"))
+               (file-name (git-file-name name version))
+               (modules '((guix build utils)))
+               (snippet
+                '(begin
+                   ;; Delete the bundled copy of libuv.
+                   (delete-file-recursively "uv")
+                   (substitute* "configure.ac"
+                     (("AC_CONFIG_SUBDIRS\\(\\[uv\\]\\)") ""))
+                   (substitute* "Makefile.am"
+                     (("SUBDIRS = uv") "\n")
+                     (("\\$\\(top_builddir\\)/uv/libuv.la") "-luv")
+
+                     ;; Make sure the 'hnsd' binary is installed and
+                     ;; dynamically-linked.
+                     (("noinst_PROGRAMS") "bin_PROGRAMS")
+                     (("hnsd_LDFLAGS = -static") ""))
+
+                   ;; This script tries to chdir to "uv" and doesn't do more
+                   ;; than "autoreconf" so remove it.
+                   (delete-file "autogen.sh")
+                   #t))))
+     (build-system gnu-build-system)
+     (arguments
+      '(#:configure-flags '("--disable-static"))) ;no need for libhsk.a
+     (native-inputs
+      `(("autoconf" ,autoconf)
+        ("automake" ,automake)
+        ("libtool" ,libtool)))
+     (inputs
+      `(("unbound" ,unbound)
+        ("libuv" ,libuv)))
+     (home-page "https://www.handshake.org/")
+     (synopsis "Resolver daemon for the Handshake naming protocol")
+     (description
+      "@command{hnsd} is a @dfn{host name resolver} for the Handshake Naming
+System (HNS) peer-to-peer network.")
+     (license license:expat))))