Ports: Add GLTron

The patches mainly convert this SDL1 game to SDL2. It has some
graphical artifacts, but it's playable!

Ports/gltron/package.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env -S bash ../.port_include.sh
+port=gltron
+useconfigure="true"
+version="0.70"
+files="http://mirror.sobukus.de/files/grimoire/games-arcade-2d/gltron-${version}-source.tar.gz gltron-${version}-source.tar.gz e0c8ebb41a18a1f8d7302a9c2cb466f5b1dd63e9a9966c769075e6b6bdad8bb0"
+auth_type=sha256
+depends=("SDL_sound" "SDL2")
+configopts=(
+    "--disable-warn"
+)
+
+launcher_name="GLTron"
+launcher_category="Games"
+launcher_command="/usr/local/bin/gltron"
+icon_file="art/default/gltron.png"
+
+pre_configure() {
+    export CPPFLAGS="-I${SERENITY_INSTALL_ROOT}/usr/include/LibGL -I${SERENITY_INSTALL_ROOT}/usr/local/include/SDL2"
+    export LIBS="-lSDL2_sound"
+    export SDL_CONFIG="${SERENITY_INSTALL_ROOT}/usr/local/bin/sdl2-config"
+}
+
+post_configure() {
+    unset CPPFLAGS
+    unset LIBS
+    unset SDL_CONFIG
+}