Install instructions for Gentoo (#352)

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

Add install instructions for Gentoo

README.md

@@ -43,6 +43,12 @@ Options:
 See 'gpclient help <command>' for more information on a specific command.
 ```
 
+To use the default browser for authentication with the CLI version, you need to use the following command:
+
+```bash
+sudo -E gpclient connect --default-browser <portal>
+```
+
 ### GUI
 
 The GUI version is also available after you installed it. You can launch it from the application menu or run `gpclient launch-gui` in the terminal.
@@ -70,7 +76,7 @@ sudo apt-get install globalprotect-openconnect
 
 #### **Ubuntu 24.04**
 
-The `libwebkit2gtk-4.0-37` was [removed](https://bugs.launchpad.net/ubuntu/+source/webkit2gtk/+bug/2061914) from its repo, before [the issue](https://github.com/yuezk/GlobalProtect-openconnect/issues/351) gets resolved, you need to install them manually:
+The `libwebkit2gtk-4.0-37` package was [removed](https://bugs.launchpad.net/ubuntu/+source/webkit2gtk/+bug/2061914) from its repo, before [the issue](https://github.com/yuezk/GlobalProtect-openconnect/issues/351) gets resolved, you need to install them manually:
 
 ```bash
 wget http://launchpadlibrarian.net/704701349/libwebkit2gtk-4.0-37_2.43.3-1_amd64.deb
@@ -87,10 +93,10 @@ The latest package is not available in the PPA either, but you still needs to ad
 
 #### Install from deb package
 
-Download the latest deb package from [releases](https://github.com/yuezk/GlobalProtect-openconnect/releases) page. Then install it with `dpkg`:
+Download the latest deb package from [releases](https://github.com/yuezk/GlobalProtect-openconnect/releases) page. Then install it with `apt`:
 
 ```bash
-sudo dpkg -i globalprotect-openconnect_*.deb
+sudo apt install --fix-broken globalprotect-openconnect_*.deb
 ```
 
 ### Arch Linux / Manjaro
@@ -137,6 +143,30 @@ Download the latest RPM package from [releases](https://github.com/yuezk/GlobalP
 ```bash
 sudo rpm -i globalprotect-openconnect-*.rpm
 ```
+### Gentoo
+
+Install from the ```rios``` or ```slonko``` overlays.  Example using rios:
+
+#### 1. Enable the overlay
+```
+sudo eselect repository enable rios
+```
+
+#### 2. Sync with the repository
+
+  - If you have eix installed, use it:
+```
+sudo eix-sync
+```
+  - Otherwise, use:
+```
+sudo emerge --sync
+```
+
+#### 3. Install
+
+```sudo emerge globalprotect-openconnect```
+
 
 ### Other distributions