libgedit-gtksourceview: init at 299.0.5

Version scheme is now documented in upstream README.md, which suggests
that even 299.x.y can be stable as long as minor version is even.

pkgs/by-name/li/libgedit-gtksourceview/nix-share-path.patch

@@ -0,0 +1,11 @@
+--- a/gtksourceview/gtksourceutils.c
++++ b/gtksourceview/gtksourceutils.c
+@@ -232,6 +232,8 @@
+ 							 NULL));
+ 	}
+ 
++	g_ptr_array_add (dirs, g_build_filename (DATADIR, GSV_DATA_SUBDIR, basename, NULL));
++
+ 	g_ptr_array_add (dirs, NULL);
+ 
+ 	return (gchar **) g_ptr_array_free (dirs, FALSE);

pkgs/by-name/li/libgedit-gtksourceview/package.nix

@@ -0,0 +1,69 @@
+{ stdenv
+, lib
+, fetchFromGitHub
+, docbook-xsl-nons
+, gobject-introspection
+, gtk-doc
+, meson
+, ninja
+, pkg-config
+, libxml2
+, glib
+, gtk3
+, shared-mime-info
+, gitUpdater
+}:
+
+stdenv.mkDerivation (finalAttrs: {
+  pname = "libgedit-gtksourceview";
+  version = "299.0.5";
+
+  outputs = [ "out" "dev" "devdoc" ];
+
+  src = fetchFromGitHub {
+    owner = "gedit-technology";
+    repo = "libgedit-gtksourceview";
+    rev = finalAttrs.version;
+    hash = "sha256-PQ7cpul9h1JzywDWm9YyD95B1ONSdUUk0EQJMEGoRN0=";
+  };
+
+  patches = [
+    # By default, the library loads syntaxes from XDG_DATA_DIRS and user directory
+    # but not from its own datadr (it assumes it will be in XDG_DATA_DIRS).
+    # Since this is not generally true with Nix, let’s add $out/share unconditionally.
+    ./nix-share-path.patch
+  ];
+
+  nativeBuildInputs = [
+    docbook-xsl-nons
+    gobject-introspection
+    gtk-doc
+    meson
+    ninja
+    pkg-config
+  ];
+
+  buildInputs = [
+    libxml2
+  ];
+
+  propagatedBuildInputs = [
+    # Required by libgedit-gtksourceview-300.pc
+    glib
+    gtk3
+    # Used by gtk_source_language_manager_guess_language
+    shared-mime-info
+  ];
+
+  passthru.updateScript = gitUpdater {
+    odd-unstable = true;
+  };
+
+  meta = with lib; {
+    description = "Source code editing widget for GTK";
+    homepage = "https://github.com/gedit-technology/libgedit-gtksourceview";
+    license = licenses.lgpl21Plus;
+    maintainers = with maintainers; [ bobby285271 ];
+    platforms = platforms.linux;
+  };
+})