Export APPDIR and this_dir in generated scripts

Author: TheAssassin

ldnp/abstractpackager.py

@@ -158,7 +158,14 @@ def create_binary_script(script_path: str | os.PathLike, target_binary: str | os
                             "",
                             "set -e",
                             "",
-                            f'script_dir="{shlex.quote(str(self.appdir_installed_path))}/apprun-hooks"',
+                            "# might be used by some AppRun scripts, e.g., craft runenv hook",
+                            f"this_dir={shlex.quote(str(self.appdir_installed_path))}",
+                            "",
+                            "# might be used by some other scripts, generally a good idea to set it",
+                            'APPDIR="this_dir"',
+                            "export APPDIR",
+                            "",
+                            f'script_dir="$APPDIR/apprun-hooks"',
                             f'if [ -d "$script_dir" ]; then',
                             '    for script in "$script_dir"/*; do',
                             '        . "$script"',