Merge pull request #848 from rocus/next

editted README.md: xxd added

Author: AlbrechtL

README.md

@@ -143,7 +143,7 @@ sudo apt install git build-essential
 2. Install the following non-Qt packages
 
 ```
-sudo apt install libfaad-dev libmpg123-dev libfftw3-dev librtlsdr-dev libusb-1.0-0-dev mesa-common-dev libglu1-mesa-dev libpulse-dev libsoapysdr-dev libairspy-dev libmp3lame-dev libflac++-dev
+sudo apt install libfaad-dev libmpg123-dev libfftw3-dev librtlsdr-dev libusb-1.0-0-dev mesa-common-dev libglu1-mesa-dev libpulse-dev libsoapysdr-dev libairspy-dev libmp3lame-dev libflac++-dev xxd
 ```
 
 3. Install the Qt via the [Qt online installer](https://www.qt.io/download-qt-installer-oss). It is recommend to use the newest Qt version. Besids Qt you need the additional Qt libraries: