fix signal handler

What's New?

1. Fixed signal handling in systemd: #969
2. Special loong64（中国龙芯）(updated 20241001) :
   kcptun-linux-loong64-20240919.tar.gz

Building information

$ go version
[kcptun-linux-loong64-20240919.tar.gz](https://github.com/user-attachments/files/17202697/kcptun-linux-loong64-20240919.tar.gz)

go version go1.23.1 linux/amd64

$ date
Thu Sep 19 18:36:24 CST 2024

$ ./build-release.sh
Setting GO111MODULE to on
a8399090fac384754517652c83ead8b4522bf128  kcptun-linux-amd64-20240919.tar.gz
ed8cc19921fd4700d1494f53c991c25f47620ecf  kcptun-darwin-amd64-20240919.tar.gz
c0035c83d85d13aa700723823a0fd194cd4c3852  kcptun-windows-amd64-20240919.tar.gz
95a7f42d3ef686d3013a7099ceaf0dbeb579ce67  kcptun-freebsd-amd64-20240919.tar.gz
d5cf1623e1750cc21441df878d84bfe024893185  kcptun-linux-386-20240919.tar.gz
448a6e4e588afd1f1c1a256adfb590c5aa533105  kcptun-windows-386-20240919.tar.gz
c26962b4ab962e3d15ea0f2382284d005c962d72  kcptun-linux-arm5-20240919.tar.gz
064b0c4c56c8721f174883a0e8479f3a9660ee44  kcptun-linux-arm6-20240919.tar.gz
a0be1028abf3ff578f15b09bc32c8989f1290de0  kcptun-linux-arm7-20240919.tar.gz
eb4e21cb0cdc19fcfa7412393d22bd23047c64d6  kcptun-linux-arm64-20240919.tar.gz
3803c499486241f24ac3cc2a91f5cbadd86076a6  kcptun-darwin-arm64-20240919.tar.gz
f6cf4032d3d445794491a55ea9be7292bab5bd8b  kcptun-windows-arm64-20240919.tar.gz
c3d26504b916acb4e87da78702ed82fcba42b441  kcptun-linux-mipsle-20240919.tar.gz
92177273155e611fd9a3196b5391e513533afe80  kcptun-linux-mips-20240919.tar.gz

(龙芯）
3786cd29e5ed943acc0823af38e8aeb820af1e3f332f556d9d9ccfe5bb1abbcc  build/kcptun-linux-loong64-20240919.tar.gz

What's Changed

• Bump golang.org/x/crypto from 0.26.0 to 0.27.0 by @dependabot in #968

Full Changelog: v20240906...v24240919