Add chacha-sys crate (#4620)

* af9ff9c7f9/src/cpu-crypt

* Add chacha-sys crate

* Remove chacha feature

* Remove erasure feature

* Add .gitignore

chacha-sys/src/lib.rs

@@ -0,0 +1,21 @@
+extern "C" {
+    fn chacha20_cbc_encrypt(
+        input: *const u8,
+        output: *mut u8,
+        in_len: usize,
+        key: *const u8,
+        ivec: *mut u8,
+    );
+}
+
+pub fn chacha_cbc_encrypt(input: &[u8], output: &mut [u8], key: &[u8], ivec: &mut [u8]) {
+    unsafe {
+        chacha20_cbc_encrypt(
+            input.as_ptr(),
+            output.as_mut_ptr(),
+            input.len(),
+            key.as_ptr(),
+            ivec.as_mut_ptr(),
+        );
+    }
+}