Set CPATH in shell.nix for clangd

.nix/default.nix

@@ -15,7 +15,7 @@ let
 		sha256 = "0rkw9k98qy7ifwypkh2fqhdn7y2qphy2f8xjisj0cyp5pjja62im";
 	};
 
-in import "${gotk4-nix}/${action}.nix" {
+in import "${gotk4-nix}/${action}.nix" rec {
 	base = {
 		pname   = "gotk4";
 		version = "dev";
@@ -44,4 +44,7 @@ in import "${gotk4-nix}/${action}.nix" {
 			})
 		];
 	};
+	passthru = {
+		inherit pkgs;
+	};
 }

shell.nix

@@ -1 +1,30 @@
-{}: import ./.nix { action = "shell"; }
+{ }:
+
+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
+	'';
+})