Change patch to patchelf (#3935)

docs/demo_guides/x86.md

@@ -4,10 +4,10 @@
 
 Paddle-Lite 支持在Docker或Linux环境编译x86预测库。环境搭建参考[环境准备](../user_guides/source_compile)。
 
-如果编译python库(`build_python=ON`)需要额外安装`python-dev`和`patch`
+如果编译python库(`build_python=ON`)需要额外安装`python-dev`和`patchelf`
 
 ```shell
-apt-get install patch
+apt-get install patchelf
 apt-get install python && apt-get install python-dev
 ```