gnu: Add r-rngtools.

* gnu/packages/statistics.scm (r-rngtools): New variable.

gnu/packages/statistics.scm

@@ -2094,6 +2094,32 @@ (define-public r-registry
 package registries.")
      (license license:gpl2+)))
 
+(define-public r-rngtools
+  (package
+    (name "r-rngtools")
+    (version "1.2.4")
+    (source
+     (origin
+       (method url-fetch)
+       (uri (cran-uri "rngtools" version))
+       (sha256
+        (base32
+         "1fcgfqrrb48z37xgy8sffx91p9irp39yqzxv7nqp1x2hnwsrh097"))))
+    (build-system r-build-system)
+    (propagated-inputs
+     `(("r-digest" ,r-digest)
+       ("r-pkgmaker" ,r-pkgmaker)
+       ("r-stringr" ,r-stringr)))
+    (home-page "https://renozao.github.io/rngtools")
+    (synopsis "Utility functions for working with random number generators")
+    (description
+     "This package contains a set of functions for working with Random Number
+Generators (RNGs).  In particular, it defines a generic S4 framework for
+getting/setting the current RNG, or RNG data that are embedded into objects
+for reproducibility.  Notably, convenient default methods greatly facilitate
+the way current RNG settings can be changed.")
+    (license license:gpl3+)))
+
 (define-public r-r-methodss3
   (package
     (name "r-r-methodss3")