warning: `rust_task_is_unwinding` redeclared with a different signature
  --> $DIR/issue-1866.rs:23:13
   |
LL |             pub fn rust_task_is_unwinding(rt: *const rust_task) -> bool;
   |             ------------------------------------------------------------ `rust_task_is_unwinding` previously declared here
...
LL |             pub fn rust_task_is_unwinding(rt: *const rust_task) -> bool;
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this signature doesn't match the previous declaration
   |
   = note: expected `unsafe extern "C" fn(*const usize) -> bool`
              found `unsafe extern "C" fn(*const bool) -> bool`
note: the lint level is defined here
  --> $DIR/issue-1866.rs:4:9
   |
LL | #![warn(clashing_extern_declarations)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: 1 warning emitted