This makes it easier to switch between check/clippy and build.
Otherwise, unless you use the same exact RUSTFLAGS and parameters,
Cargo will rebuild everything (throwing away the build cache).
* Now supports building examples with `--example <name>`.
* Now prints out each stage as it executes.
* Now uses the target dir found by `cargo metadata`, since it may not be
in the current directory (ex. workspaces).
The default-linker-libraries flag requires a change in the rustc target
to set `no_default_libraries` to false.
The muldefs flag isn't necessary anymore. I think the removal of static
libs (ex. linker fix and pthread_3ds) might have fixed this issue.
The __3DS__ flag doesn't seem to have been necessary at all.
Similarly, `-Z unstable-options` isn't needed for cargo.