gnu: networking: Add czmq.

* gnu/packages/networking.scm (czmq): New variable.

gnu/packages/networking.scm

@@ -267,6 +267,42 @@ (define-public zeromq
 more.")
     (license license:lgpl3+)))
 
+(define-public czmq
+  (package
+    (name "czmq")
+    (version "4.1.0")
+    (source (origin
+              (method url-fetch)
+              (uri (string-append
+                    "https://github.com/zeromq/" name
+                    "/releases/download/v" version
+                    "/" name "-" version ".tar.gz"))
+              (sha256
+               (base32
+                "04gwf61rijwm6b2wblwv8gky1gdrbfmg1d19hf72kdc691ds7vrv"))))
+    (build-system gnu-build-system)
+    (arguments
+     '(;; TODO Tests fail for some reason:
+       ;;  * zauth: OK
+       ;;  * zbeacon: OK (skipping test, no UDP broadcasting)
+       ;; E: (czmq_selftest) 18-02-24 16:25:52 No broadcast interface found, (ZSYS_INTERFACE=lo)
+       ;; make[2]: *** [Makefile:2245: check-local] Segmentation fault
+       ;; make[2]: Leaving directory '/tmp/guix-build-czmq-4.1.0.drv-0/czmq-4.1.0'
+       ;; make[1]: *** [Makefile:2032: check-am] Error 2
+       ;; make[1]: Leaving directory '/tmp/guix-build-czmq-4.1.0.drv-0/czmq-4.1.0'
+       ;; make: *** [Makefile:1588: check-recursive] Error 1
+       ;; phase `check' failed after 19.4 seconds
+       #:tests? #f
+       #:configure-flags '("--enable-drafts")))
+    (inputs
+     `(("zeromq" ,zeromq)))
+    (home-page "http://zeromq.org")
+    (synopsis "High-level C bindings for ØMQ")
+    (description
+     "czmq provides bindings for the ØMQ core API that hides the differences
+between different versions of ØMQ.")
+    (license license:mpl2.0)))
+
 (define-public librdkafka
   (package
     (name "librdkafka")