gnu: Add libretro-nestopia.

* gnu/packages/emulators.scm (libretro-nestopia): New variable.

Change-Id: I25d44dea48a1b01354ee83eb7b39a9b4ecd9aa9e

gnu/packages/emulators.scm

@@ -26,6 +26,7 @@
 ;;; Copyright © 2025 Andrew Wong <wongandj@icloud.comg>
 ;;; Copyright © 2025 Anderson Torres <anderson.torres.8519@gmail.com>
 ;;; Copyright © 2025 Laura Kirsch <laurakirsch240406@gmail.com>
+;;; Copyright © 2026 Nikita Alkhovik <forgoty13@gmail.com>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -4382,6 +4383,47 @@ of the Nestopia emulator.")
     (license (list license:gpl2+        ;this project
                    license:lgpl2.1+)))) ;nes_ntsc source files
 
+(define-public libretro-nestopia
+  (package
+    (inherit jg-nestopia)
+    (name "libretro-nestopia")
+    (properties '((commit . "473d3072be67fa2542ca833c274ef6682cf0f0bc")
+                  (revision . "0")))
+    (version (git-version "2.0" ;from libretro/libretro_core_options.h
+                          (assoc-ref properties
+                                     'revision)
+                          (assoc-ref properties
+                                     'commit)))
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://github.com/libretro/nestopia")
+             (commit (assoc-ref properties
+                                'commit))))
+       (file-name (git-file-name "libretro-nestopia" version))
+       (sha256
+        (base32 "01gfwm6ig9ih4yw34fw4hdg6qsyzyjx3v4rvzb0bwk31453v9vhx"))))
+    (arguments
+     (list
+      #:tests? #f ;no test suite
+      #:phases
+      #~(modify-phases %standard-phases
+          (add-after 'unpack 'change-to-build-dir
+            (lambda _
+              (chdir "libretro")))
+          (delete 'configure)
+          (replace 'install
+            (lambda _
+              (let ((out (string-append #$output "/lib/libretro")))
+                (mkdir-p out)
+                (install-file "nestopia_libretro.so" out)))))))
+    (synopsis "Libretro port of Nestopia NES/Famicom emulator")
+    (description
+     "This is the libretro port of the Nestopia emulator, based on the de facto
+  upstream Nestopia JG fork, which lives at: https://gitlab.com/jgemu/nestopia.
+  The libretro port contains an additional overclocking feature.")))
+
 (define-public jg-cega
   (package
     (name "jg-cega")