gnu: Add mlucas.

* gnu/packages/maths.scm (mlucas): New variable.

gnu/packages/maths.scm

@@ -4827,3 +4827,54 @@ (define-public dune-pdelab
 built on top of DUNE, the Distributed and Unified Numerics Environment.")
     ;; Either GPL version 2 with "runtime exception" or LGPLv3+.
     (license (list license:lgpl3+ license:gpl2))))
+
+(define-public mlucas
+  (package
+    (name "mlucas")
+    (version "18")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (string-append
+             "https://mersenneforum.org/mayer/src/C/mlucas_v" version ".txz"))
+       (sha256
+        (base32
+         "1ax12qj9lyvnx4vs3gx7l8r3wx5gjbsdswp5f00ik9z0wz7xf297"))))
+    (build-system gnu-build-system)
+    (inputs
+     `(("python2" ,python-2)))
+    (arguments
+     `(#:tests? #f ; no tests
+       #:phases
+       (modify-phases %standard-phases
+         (replace 'configure
+           (lambda _
+             (chdir "src")
+             (call-with-output-file "Makefile"
+               (lambda (port)
+                 (format port "CC = gcc
+CFLAGS = -O3 ~a -DUSE_THREADS
+LDLIBS = -lm -lpthread -lrt
+Mlucas: $(addsuffix .o,$(basename $(wildcard *.c)))
+"
+                         ,(let ((system (or (%current-target-system)
+                                            (%current-system))))
+                            (cond
+                             ((string-prefix? "x86_64" system) "-DUSE_SSE2")
+                             (else ""))))))
+             #t))
+         (replace 'install
+           (lambda* (#:key outputs #:allow-other-keys)
+             (let ((bin (string-append (assoc-ref outputs "out") "/bin")))
+               (install-file "Mlucas" bin)
+               (install-file "primenet.py" bin))
+             #t)))))
+    (home-page "https://www.mersenne.org")
+    (synopsis "Great Internet Mersenne Prime Search (GIMPS) distributed computing client")
+    (description "Mlucas performs Lucas-Lehmer primality testing of Mersenne
+numbers in search of a world-record prime.  You may use it to test any
+suitable number as you wish, but it is preferable that you do so in a
+coordinated fashion, as part of the Great Internet Mersenne Prime
+Search (GIMPS).  Mlucas also includes a simple Python script for assignment
+management via the GIMPS project's Primenet server.")
+    (license license:gpl2+)))