Build GNU patch with xattr support in std.utils

[deciduously]

Currently, the build of GNU patch included in the std.utils set isn't compiled against libattr on Linux, which may cause patch operations to strip or fail to preserve xattrs required by the Tangram system. Ensure this dependency is available to the build process.

Additionally, ensure the patch execuable provided on macOS preserves xattrs, which may involve using the Apple Open Source version instead of GNU as we currently do for the install executable.

• linux
• macOS