Add coredump feature and print PC

package/luci/files/luci/i18n/smartdns.zh-cn.po

@@ -16,6 +16,12 @@ msgstr "SmartDNS是一个本地高性能DNS服务器，支持避免域名污染
 msgid "Custom Settings"
 msgstr "自定义设置"
 
+msgid "Generate Coredump"
+msgstr "生成coredump"
+
+msgid "Generate Coredump file when smartdns crash, coredump file is located at /tmp/smartdns.xxx.core."
+msgstr "当smartdns异常时生成coredump文件，coredump文件在/tmp/smartdns.xxx.core."
+
 msgid "Server Name"
 msgstr "服务器名称"
 

package/luci/files/luci/model/cbi/smartdns/smartdns.lua

@@ -103,6 +103,13 @@ function custom.write(self, section, value)
 	nixio.fs.writefile("/etc/smartdns/custom.conf", value)
 end
 
+o = s:taboption("custom", Flag, "coredump", translate("Generate Coredump"), translate("Generate Coredump file when smartdns crash, coredump file is located at /tmp/smartdns.xxx.core."))
+o.rmempty     = false
+o.default     = o.disabled
+o.cfgvalue    = function(...)
+    return Flag.cfgvalue(...) or "0"
+end
+
 -- Upstream servers
 s = m:section(TypedSection, "server", translate("Upstream Servers"), translate("Upstream Servers, support UDP, TCP protocol. " ..
 	"Please configure multiple DNS servers, including multiple foreign DNS servers."))