Add test of macro calls inside extern block

Author: dtolnay

tests/source/extern.rs

@@ -77,3 +77,16 @@ libc::c_long;
 extern {
 
 }
+
+macro_rules! x {
+    ($tt:tt) => {};
+}
+
+extern "macros" {
+    x!(ident);
+    // x!(#); FIXME
+    x![ident];
+    // x![#]; FIXME
+    x! {ident}
+    x! {#}
+}

tests/target/extern.rs

@@ -82,3 +82,16 @@ extern "C" {
 }
 
 extern "C" {}
+
+macro_rules! x {
+    ($tt:tt) => {};
+}
+
+extern "macros" {
+    x!(ident);
+    // x!(#); FIXME
+    x![ident];
+    // x![#]; FIXME
+    x! {ident}
+    x! {#}
+}