A directory-category for terminal emulators

This is a mostly cosmetical commit, in the sense it doesn't change the contents
of any package, but reorganizes the overall Nixpkgs expressions.

Terminal emulators are an ubiquitous tool for any Unix user; even the beginners
are routinely familiarized to it. And, manifestly, there are many
implementations of terminal emulators out there, from those traditionally made
in C and C++ to those written in Haskell and Go.

Terminal emulators deserve more highlight. This commit does that by creating a
category for them.

pkgs/applications/terminal-emulators/roxterm/default.nix

@@ -0,0 +1,47 @@
+{ at-spi2-core, cmake, dbus, dbus-glib, docbook_xsl, epoxy, fetchpatch, fetchFromGitHub
+, glib, gtk3, harfbuzz, libXdmcp, libXtst, libpthreadstubs
+, libselinux, libsepol, libtasn1, libxkbcommon, libxslt, p11-kit, pcre2
+, pkgconfig, stdenv, utillinuxMinimal, vte, wrapGAppsHook, xmlto
+}:
+
+stdenv.mkDerivation rec {
+  pname = "roxterm";
+  version = "3.7.5";
+
+  src = fetchFromGitHub {
+    owner = "realh";
+    repo = "roxterm";
+    rev = version;
+    sha256 = "042hchvgk9jzz035zsgnfhh8105zvspbzz6b78waylsdlgqn0pp1";
+  };
+
+  patches = [
+    # This is the commit directly after v3.7.5.  It is needed to get roxterm to
+    # build correctly.  It can be removed when v3.7.6 (or v3.8.0) has been
+    # released.
+    (fetchpatch {
+      url = "https://github.com/realh/roxterm/commit/f7c38fd48bd1810e16d82794bdfb61a9760a2fe1.patch";
+      sha256 = "1v77b7ilgf8zy1npxxcyc06mq6lck6bi6lw4aksnq3mi61n5znmx";
+    })
+  ];
+
+  nativeBuildInputs = [ cmake pkgconfig wrapGAppsHook libxslt ];
+
+  buildInputs =
+    [ gtk3 dbus dbus-glib vte pcre2 harfbuzz libpthreadstubs libXdmcp
+      utillinuxMinimal glib docbook_xsl xmlto libselinux
+      libsepol libxkbcommon epoxy at-spi2-core libXtst libtasn1 p11-kit
+    ];
+
+  meta = with stdenv.lib; {
+    homepage = "https://github.com/realh/roxterm";
+    license = licenses.gpl3;
+    description = "Tabbed, VTE-based terminal emulator";
+    longDescription = ''
+      Tabbed, VTE-based terminal emulator. Similar to gnome-terminal without
+      the dependencies on Gnome.
+    '';
+    maintainers = with maintainers; [ cdepillabout ];
+    platforms = platforms.linux;
+  };
+}