Don't assume_init on uninitialized memory (#87)

Fixes: #86

src/linux/libunwind/mod.rs

@@ -45,13 +45,13 @@ impl Unwinder {
     pub fn cursor(&self, thread: &crate::Thread) -> Result<Cursor> {
         unsafe {
             let upt = _UPT_create(thread.id()? as _);
-            let mut cursor = std::mem::MaybeUninit::uninit().assume_init();
-            let ret = init_remote(&mut cursor, self.addr_space, upt);
+            let mut cursor = std::mem::MaybeUninit::uninit();
+            let ret = init_remote(cursor.as_mut_ptr(), self.addr_space, upt);
             if ret != 0 {
                 return Err(crate::Error::LibunwindError(Error::from(-ret)));
             }
             Ok(Cursor {
-                cursor,
+                cursor: cursor.assume_init(),
                 upt,
                 initial_frame: true,
             })
@@ -106,7 +106,7 @@ impl Cursor {
         unsafe {
             let mut name = vec![0_u8 as c_char; 128];
             let cursor = &self.cursor as *const _ as *mut _;
-            let mut raw_offset = std::mem::MaybeUninit::uninit().assume_init();
+            let mut raw_offset = 0;
 
             loop {
                 match get_proc_name(cursor, name.as_mut_ptr(), name.len(), &mut raw_offset) {