git-evtag: init at 2022.1

https://github.com/cgwalters/git-evtag

This is used for tagging GNOME releases:
https://handbook.gnome.org/maintainers/making-a-release.html#tagging-as-the-signal-for-the-release

pkgs/by-name/gi/git-evtag/package.nix

@@ -0,0 +1,47 @@
+{
+  lib,
+  stdenv,
+  fetchFromGitHub,
+  meson,
+  ninja,
+  pkg-config,
+  libxslt,
+  docbook-xsl-nons,
+  glib,
+  libgit2,
+}:
+
+stdenv.mkDerivation rec {
+  pname = "git-evtag";
+  version = "2022.1";
+
+  src = fetchFromGitHub {
+    owner = "cgwalters";
+    repo = "git-evtag";
+    rev = "v${version}";
+    hash = "sha256-+nGPfISDpf2YMeCtPgaOOwzYijTPGRVCzT+74sGZ3JY=";
+  };
+
+  nativeBuildInputs = [
+    meson
+    ninja
+    pkg-config
+    # Man page
+    libxslt
+    docbook-xsl-nons
+  ];
+
+  buildInputs = [
+    glib
+    libgit2
+  ];
+
+  meta = {
+    description = "Extended verification for git tags";
+    homepage = "https://github.com/cgwalters/git-evtag";
+    license = lib.licenses.lgpl2Plus;
+    maintainers = with lib.maintainers; [ jtojnar ];
+    mainProgram = "git-evtag";
+    platforms = lib.platforms.unix;
+  };
+}