use latest version of libc, remove obsolete code

src/libunwind/Cargo.toml

@@ -17,7 +17,7 @@ doc = false
 
 [dependencies]
 core = { path = "../libcore" }
-libc = { version = "0.2.43", features = ['rustc-dep-of-std'], default-features = false }
+libc = { version = "0.2.65", features = ['rustc-dep-of-std'], default-features = false }
 compiler_builtins = "0.1.0"
 cfg-if = "0.1.8"
 

src/libunwind/libunwind.rs

@@ -1,26 +1,7 @@
 #![allow(nonstandard_style)]
 
-#[cfg(not(target_os = "hermit"))]
 use libc::{c_int, c_void, uintptr_t};
 
-#[cfg(target_os = "hermit")]
-pub type c_int = i32;
-
-#[cfg(target_os = "hermit")]
-pub type uintptr_t = usize;
-
-#[cfg(target_os = "hermit")]
-#[repr(u8)]
-#[allow(missing_copy_implementations)]
-#[allow(missing_debug_implementations)]
-pub enum c_void {
-    // Two dummy variants so the #[repr] attribute can be used.
-    #[doc(hidden)]
-    __variant1,
-    #[doc(hidden)]
-    __variant2,
-}
-
 #[repr(C)]
 #[derive(Debug, Copy, Clone, PartialEq)]
 pub enum _Unwind_Reason_Code {