add g++ in ubuntu
@@ -8,7 +8,7 @@ It is easy to build Lapce from source on a GNU/Linux distribution. Cargo handles
#### Ubuntu
```sh
-sudo apt install cmake pkg-config libfontconfig-dev libgtk-3-dev
+sudo apt install cmake pkg-config libfontconfig-dev libgtk-3-dev g++
```
#### Fedora
```sh
