Add no_std support

Author: madsmtm

Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Steven Sheldon"]
 
 description = "Rust interface for Objective-C's throw and try/catch statements."
 keywords = ["objective-c", "osx", "ios"]
+categories = ["development-tools::ffi", "no-std"]
 repository = "http://github.com/SSheldon/rust-objc-exception"
 documentation = "http://ssheldon.github.io/rust-objc/objc_exception/"
 license = "MIT"

extern/exception.m

@@ -5,7 +5,8 @@ void RustObjCExceptionThrow(id exception) {
     @throw exception;
 }
 
-int RustObjCExceptionTryCatch(void (*try)(void *), void *context, id *error) {
+// We return `unsigned char`, since it is guaranteed to be an `u8` on all platforms
+unsigned char RustObjCExceptionTryCatch(void (*try)(void *), void *context, id *error) {
     @try {
         try(context);
         if (error) {

src/lib.rs

@@ -1,16 +1,21 @@
 //! Rust interface for Objective-C's `@throw` and `@try`/`@catch` statements.
 
-use std::mem;
-use std::os::raw::{c_int, c_void};
-use std::ptr;
+#![no_std]
+
+#[cfg(test)]
+extern crate alloc;
+
+use core::ffi::c_void;
+use core::mem;
+use core::ptr;
 
 #[link(name = "objc", kind = "dylib")]
 extern { }
 
 extern {
     fn RustObjCExceptionThrow(exception: *mut c_void);
     fn RustObjCExceptionTryCatch(try: extern fn(*mut c_void),
-            context: *mut c_void, error: *mut *mut c_void) -> c_int;
+            context: *mut c_void, error: *mut *mut c_void) -> u8; // std::os::raw::c_uchar
 }
 
 /// An opaque type representing any Objective-C object thrown as an exception.
@@ -74,7 +79,9 @@ pub unsafe fn try<F, R>(closure: F) -> Result<R, *mut Exception>
 
 #[cfg(test)]
 mod tests {
-    use std::ptr;
+    use alloc::string::ToString;
+    use core::ptr;
+
     use super::{throw, try};
 
     #[test]