gnu: Add julius.

* gnu/packages/games.scm (julius): New variable.

gnu/packages/games.scm

@@ -43,7 +43,7 @@
 ;;; Copyright © 2019 Jesse Gibbons <jgibbons2357+guix@gmail.com>
 ;;; Copyright © 2019 Dan Frumin <dfrumin@cs.ru.nl>
 ;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
-;;; Copyright © 2019 Timotej Lazar <timotej.lazar@araneo.si>
+;;; Copyright © 2019, 2020 Timotej Lazar <timotej.lazar@araneo.si>
 ;;; Copyright © 2019 Josh Holland <josh@inv.alid.pw>
 ;;; Copyright © 2017, 2019 Hartmut Goebel <h.goebel@crazy-compilers.com>
 ;;;
@@ -739,6 +739,34 @@ automata.  The following features are available:
 @end enumerate")
     (license license:gpl2+)))
 
+(define-public julius
+  (package
+    (name "julius")
+    (version "1.2.0")
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/bvschaik/julius.git")
+             (commit (string-append "v" version))))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "0kgyzfjii4dhpy2h05977alwdmxyxb4jxznnrhlgb21m0ybncmvp"))))
+    (build-system cmake-build-system)
+    (inputs
+     `(("sdl2" ,sdl2)
+       ("sdl2-mixer" ,sdl2-mixer)))
+    (home-page "https://github.com/bvschaik/julius")
+    (synopsis "Re-implementation of Caesar III game engine")
+    (description
+     "Engine for Caesar III, a city-building real-time strategy game.
+Julius includes some UI enhancements while preserving the logic (including
+bugs) of the original game, so that saved games are compatible.  This package
+does not include game data.")
+    (license (list license:agpl3
+                   license:expat        ; ext/dirent
+                   license:zlib))))     ; ext/tinyfiledialogs
+
 (define-public meandmyshadow
   (package
     (name "meandmyshadow")