Add dependency checking to install script

install.sh

@@ -1,5 +1,10 @@
 #!/usr/bin/env sh
 
+echo "=> Checking dependencies..."
+
+command -v stow >/dev/null 2>&1 || { echo "Please install GNU Stow!"; exit 69; }
+
+sleep 0.5
 echo "=> Determining OS..."
 
 if [ "$(uname -o)" = "Android" ] || [ "$(lsb_release -si)" = "Fedora" ]; then
@@ -10,13 +15,13 @@ elif [ "$(lsb_release -si)" = "Artix" ]; then
     set -- "alacritty" "mako" "nvim" "scripts" "sway" "swaylock" "swaynag" "waybar" "zsh"
 else
     echo "OS not supported!"
-    exit 1
+    exit 420
 fi
 
 sleep 0.5
 echo "=> Installing dotfile packages..."
 
-cd -- "$(dirname -- $0)"
+cd -P -- "$(readlink -e "$(dirname "$0")")"
 
 for pkg in "$@"; do
     sleep 0.1