Add loongarch support (#116)

Signed-off-by: guoqi.chen <chenguoqi@loongson.cn>
diff --git a/ztypes_loongarchx.go b/ztypes_loongarchx.go
new file mode 100644
index 0000000..6fa946a
--- /dev/null
+++ b/ztypes_loongarchx.go
@@ -0,0 +1,12 @@
+// Created by cgo -godefs - DO NOT EDIT
+// cgo -godefs types.go
+
+// +build linux
+// +build loongarch32 loongarch64
+
+package pty
+
+type (
+	_C_int  int32
+	_C_uint uint32
+)