Add Go version guard into shell.nix

.nix/default.nix

@@ -11,10 +11,14 @@ let
 	gotk4-nix = systemPkgs.fetchFromGitHub {
 		owner  = "diamondburned";
 		repo   = "gotk4-nix";
-		rev    = "ad91dabf706946c4380d0a105f0937e4e8ffd75f";
-		sha256 = "0rkw9k98qy7ifwypkh2fqhdn7y2qphy2f8xjisj0cyp5pjja62im";
+		rev    = "4eab6a0";
+		sha256 = "sha256-WsJ2Cf1hvKT3BUYYVxQ5rNMYi6z7NWccbSsw39lgqO8=";
 	};
 
+	minGoVersion = 
+		with builtins;
+		elemAt (elemAt (split "go ([0-9][^\n]*)" (readFile ../go.mod)) 1) 0;
+
 in import "${gotk4-nix}/${action}.nix" rec {
 	base = {
 		pname   = "gotk4";
@@ -39,8 +43,14 @@ in import "${gotk4-nix}/${action}.nix" rec {
 				go =
 					let
 						upstreamPkgs = import "${gotk4-nix}/pkgs.nix" {};
+						go = upstreamPkgs.go;
 					in
-						upstreamPkgs.go;
+						with systemPkgs.lib;
+						assert assertMsg
+							(versionAtLeast go.version minGoVersion)
+							"go version ${go.version} is too old, need at least ${minGoVersion}";
+
+						go;
 			})
 		];
 	};

shell.nix

@@ -1,30 +1,8 @@
 { }:
 
 let
-	cPackages = [
-		"gtk4"
-		"gtk3"
-	];
-
 	shell = import ./.nix { action = "shell"; };
 	pkgs  = shell.pkgs;
 in
 
-shell.overrideAttrs (old: {
-	shellHook = ''
-		${old.shellHook or ""}
-
-		for pkg in ${pkgs.lib.concatStringsSep " " cPackages}; do
-			__cpath=$(pkg-config $pkg --cflags-only-I | sed 's/ -I/:/g' | sed 's/^-I//')
-			if [[ $__cpath == "" ]]; then
-				continue
-			fi
-
-			if [[ -z $CPATH ]]; then
-				export CPATH=$__cpath
-			else
-				export CPATH=$CPATH:$__cpath
-			fi
-		done
-	'';
-})
+shell