doc: Make all doctests buildable once more

src/gpio/mod.rs

@@ -88,7 +88,12 @@ impl GPIO {
     /// Create a GPIO from its port and pin numbers
     ///
     /// ```
+    /// # #![no_std]
+    /// # #![no_main]
+    /// # fn f() {
+    /// use riot_wrappers::gpio::GPIO;
     /// let pin_c8 = GPIO::from_port_and_pin(3, 8);
+    /// # }
     /// ```
     ///
     /// See [from_c] for safety constraints.

src/main_module.rs

@@ -91,7 +91,8 @@ impl<F: Fn(StartToken) -> ((), EndToken)> UsableAsMain<[u8; 3]> for F {
 ///
 /// ```
 /// # #![no_std]
-/// # use riot_wrappers::riot_main;
+/// # #![no_main]
+/// use riot_wrappers::riot_main;
 /// riot_main!(main);
 ///
 /// fn main() {

src/msg/v2.rs

@@ -171,16 +171,14 @@ pub trait MessageSemantics: Sized {
     ///
     /// ```
     /// # #![no_std]
-    /// # #![feature(start)]
-    /// # #[start]
-    /// # fn main(_argc: isize, _argv: *const *const u8) -> isize {
-    /// # use riot_wrappers::msg::v2::*;
-    /// # let message_semantics = unsafe { NoConfiguredMessages::new() };
+    /// # #![no_main]
+    /// # fn f() {
+    /// use riot_wrappers::msg::v2::*;
+    /// # let message_semantics = NoConfiguredMessages; // FIXME: constructing this should not be possible publicly
     /// type NumberReceived = ReceivePort<u32, 1>;
     /// type BoolReceived = ReceivePort<bool, 2>;
     /// let (message_semantics, receive_num, send_num): (_, NumberReceived, _) = message_semantics.split_off();
     /// let (message_semantics, receive_bool, send_bool): (_, BoolReceived, _) = message_semantics.split_off();
-    /// # 0
     /// # }
     /// ```
     ///