update for new configuration options

INSTALL

@@ -36,21 +36,32 @@ Rquired software: QT, a compiler like Visual Studio, ASIO development files
 Linux:
 ------
 
-Required packages: Build-Essential, QT4 (devel packages, too!), Jack (devel packages, too!)
+Required packages: Build-Essential, QT5 (devel packages, too!), Jack (devel packages, too!)
                    On the most common Linux distributions, the following
                    command should prepare the system for compilation:
-                   sudo apt-get install build-essential libqt4-dev libjack-dev
+                   sudo apt-get install build-essential libqt5-dev libjack-dev
 
 - qmake Jamulus.pro
 - make clean
 - make
 - run ./Jamulus
 
+Note that the "make clean" is essential to remove the automatically generated Qt
+files which are present in the .tar.gz file and may not match the Qt version you
+are using.
+
 Use qmake "CONFIG+=nosound" Jamulus.pro for pure server installation which
 does not require the Jack packages.
 
-Note that the "make clean" is essential to remove the automatically generated Qt files which
+The legacy CELT support can be disabled with qmake "CONFIG+=nocelt" Jamulus.pro
-are present in the .tar.gz file and may not match the Qt version you are using.
+
+To use an external shared OPUS library instead of the built-in use
+qmake "CONFIG+=opus_shared_lib" Jamulus.pro.
+
+A desktop link file jamulus.desktop is available in the llcon/src/res directory.
+To use this file configure the software with
+qmake "CONFIG+=noupcasename" Jamulus.pro to make sure the output target name of
+this software is jamulus instead of Jamulus (see content of jamulus.desktop).
 
 Mac:
 ----