Tie the lifetime of Gfx to Console

This prevents dropping the Gfx object before the console. We want to do
this because printing after dropping gfx doesn't do anything (gfx isn't
rendering the text anymore).

Note that even though Rust doesn't understand the relationship between
Console and println, even if you don't use the console variable Rust
will prevent Gfx dropping because Console's Drop code _might_ use the
Gfx object (it doesn't, but we get the error we want anyway).

ctru-rs/src/console.rs

@@ -1,23 +1,28 @@
 use std::default::Default;
+use std::marker::PhantomData;
 
 use ctru_sys::{consoleClear, consoleInit, consoleSelect, consoleSetWindow, PrintConsole};
 
 use crate::gfx::{Gfx, Screen};
 
-pub struct Console {
+pub struct Console<'gfx> {
     context: Box<PrintConsole>,
+    _gfx: PhantomData<&'gfx ()>,
 }
 
-impl Console {
+impl<'gfx> Console<'gfx> {
     /// Initialize a console on the chosen screen, overwriting whatever was on the screen
     /// previously (including other consoles). The new console is automatically selected for
     /// printing.
-    pub fn init(_gfx: &Gfx, screen: Screen) -> Self {
+    pub fn init(_gfx: &'gfx Gfx, screen: Screen) -> Self {
         let mut context = Box::new(PrintConsole::default());
 
         unsafe { consoleInit(screen.into(), context.as_mut()) };
 
-        Console { context }
+        Console {
+            context,
+            _gfx: PhantomData,
+        }
     }
 
     /// Select this console as the current target for stdout
@@ -45,7 +50,7 @@ impl Console {
     }
 }
 
-impl Drop for Console {
+impl Drop for Console<'_> {
     fn drop(&mut self) {
         static mut EMPTY_CONSOLE: PrintConsole = unsafe { const_zero::const_zero!(PrintConsole) };