sys: Add some GNUStep objc_msg_X functions

objc/src/message/gnustep.rs

@@ -1,13 +1,8 @@
 use core::mem;
-use objc_sys::objc_super;
+use objc_sys::{objc_msg_lookup, objc_msg_lookup_super, objc_super};
 
 use super::{Encode, Message, MessageArguments, MessageError};
-use crate::runtime::{Class, Imp, Object, Sel};
-
-extern "C" {
-    fn objc_msg_lookup(receiver: *mut Object, op: Sel) -> Imp;
-    fn objc_msg_lookup_super(sup: *const objc_super, sel: Sel) -> Imp;
-}
+use crate::runtime::{Class, Object, Sel};
 
 pub unsafe fn send_unverified<T, A, R>(obj: *const T, sel: Sel, args: A) -> Result<R, MessageError>
 where
@@ -20,7 +15,7 @@ where
     }
 
     let receiver = obj as *mut T as *mut Object;
-    let msg_send_fn = objc_msg_lookup(receiver, sel);
+    let msg_send_fn = objc_msg_lookup(receiver as *mut _, sel.as_ptr() as *const _);
     objc_try!({ A::invoke(msg_send_fn, receiver, sel, args) })
 }
 
@@ -40,6 +35,6 @@ where
         receiver: receiver as *mut _,
         super_class: superclass as *const Class as *const _,
     };
-    let msg_send_fn = objc_msg_lookup_super(&sup, sel);
+    let msg_send_fn = objc_msg_lookup_super(&sup, sel.as_ptr() as *const _);
     objc_try!({ A::invoke(msg_send_fn, receiver, sel, args) })
 }

objc_sys/src/message.rs

@@ -18,6 +18,13 @@ pub struct objc_super {
     pub super_class: *const objc_class,
 }
 
+#[cfg(gnustep)]
+extern "C" {
+    pub fn objc_msg_lookup(receiver: *mut objc_object, sel: *const objc_selector) -> IMP;
+    pub fn objc_msg_lookup_super(super: *const objc_super, sel: *const objc_selector) -> IMP;
+    // objc_msg_lookup_sender
+}
+
 extern "C" {
     pub fn objc_msgSend();
     #[cfg(apple)]

objc_sys/src/various.rs

@@ -91,4 +91,7 @@ extern "C" {
     // #[deprecated = "not recommended"]
     // #[cfg(apple)]
     // pub fn _objc_flush_caches
+
+    // #[cfg(gnustep)]
+    // objc_test_capability
 }