Fix #414

Partially reverts rust-embedded/cortex-m-rt#224
to continue to use a fully-qualified path to `exception`.

Author: adamgreig

cortex-m-rt/CHANGELOG.md

@@ -7,6 +7,17 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 
+## Fixes
+
+- Fix `cortex_m_rt::exception` macro no longer being usable fully-qualified ([#414])
+
+[#414]: https://github.com/rust-embedded/cortex-m/issues/414
+
+## Notes
+
+- From this release onwards, cortex-m-rt lives in the cortex-m repository;
+  issue numbers refer there.
+
 ## [v0.7.1]
 
 ## Fixes

cortex-m-rt/macros/src/lib.rs

@@ -328,7 +328,7 @@ pub fn exception(args: TokenStream, input: TokenStream) -> TokenStream {
             f.block.stmts = iter::once(
                 syn::parse2(quote! {{
                     // check that this exception actually exists
-                    exception::#ident;
+                    cortex_m_rt::exception::#ident;
                 }})
                 .unwrap(),
             )