message: Condvar: Mark sys functions as extern "C"
  They are declared in hermit-abi as extern "C" already.
  So the current definition without extern "C" is wrong.
diff: @@ -41,7 +41,7 @@ extern "C" fn __sys_destroy_queue(ptr: usize) -> i32 {
  }
  #[no_mangle]
  -pub unsafe fn sys_destroy_queue(ptr: usize) -> i32 {
  +pub unsafe extern "C" fn sys_destroy_queue(ptr: usize) -> i32 {
  kernel_function!(__sys_destroy_queue(ptr))
  }
  @@ -82,7 +82,7 @@ extern "C" fn __sys_notify(ptr: usize, count: i32) -> i32 {
  }
  #[no_mangle]
  -pub unsafe fn sys_notify(ptr: usize, count: i32) -> i32 {
  +pub unsafe extern "C" fn sys_notify(ptr: usize, count: i32) -> i32 {
  kernel_function!(__sys_notify(ptr, count))
  }
  @@ -105,7 +105,7 @@ extern "C" fn __sys_init_queue(ptr: usize) -> i32 {
  }
  #[no_mangle]
  -pub unsafe fn sys_init_queue(ptr: usize) -> i32 {
  +pub unsafe extern "C" fn sys_init_queue(ptr: usize) -> i32 {
  kernel_function!(__sys_init_queue(ptr))
  }
  @@ -137,7 +137,7 @@ extern "C" fn __sys_add_queue(ptr: usize, timeout_ns: i64) -> i32 {
  }
  #[no_mangle]
  -pub unsafe fn sys_add_queue(ptr: usize, timeout_ns: i64) -> i32 {
  +pub unsafe extern "C" fn sys_add_queue(ptr: usize, timeout_ns: i64) -> i32 {
  kernel_function!(__sys_add_queue(ptr, timeout_ns))
  }
  @@ -163,6 +163,6 @@ extern "C" fn __sys_wait(ptr: usize) -> i32 {
  }
  #[no_mangle]
  -pub unsafe fn sys_wait(ptr: usize) -> i32 {
  +pub unsafe extern "C" fn sys_wait(ptr: usize) -> i32 {
  kernel_function!(__sys_wait(ptr))
  }
  