openbsd: add sparc64 support

src/unix/bsd/netbsdlike/openbsd/mod.rs

@@ -1438,6 +1438,9 @@ cfg_if! {
     } else if #[cfg(target_arch = "aarch64")] {
         mod aarch64;
         pub use self::aarch64::*;
+    } else if #[cfg(target_arch = "sparc64")] {
+        mod sparc64;
+        pub use self::sparc64::*;
     } else {
         // Unknown target_arch
     }

src/unix/bsd/netbsdlike/openbsd/sparc64.rs

+pub type c_long = i64;
+pub type c_ulong = u64;
+pub type c_char = i8;
+
+#[doc(hidden)]
+pub const _ALIGNBYTES: usize = 0xf;
+
+pub const _MAX_PAGE_SHIFT: u32 = 13;