[Lxde-list] How to compile lxqt from sources

[JORGE <jfs...@uc...>]

Hello, I'm training to build lxqt from the sources located at https://github.com/lxde/lxqt
following the wiki (https://github.com/lxde/lxqt/wiki). I already installed all dependences mentioned in the wiki, but
when I run "LXQT_PREFIX=/usr ./build_all.sh" it returns me this error:
>>>>>>>>>>>>>>[ERROR START]<<<<<<<<<<<<<<<<
Building: libqtxdg using externally specified options: -DCMAKE_BUILD_TYPE=debug -DCMAKE_INSTALL_PREFIX=/usr  

-- Building in SuperBuild mode. Builds all LXQt CMake projects at once.
	Autotools/Automake based projects not yet supported.
	lximage-qt also not yet supported
CMake Error at CMakeLists.txt:6 (message):
  CMAKE_PREFIX_PATH environment variable not set.  When configuring for the
  first time, make sure CMAKE_PREFIX_PATH is set to the root of the build
  directory.  It can be done by passing it to cmake as an command line
  parameter (e.g.  cmake -DCMAKE_PREFIX_PATH=path_to_your_build_dir ..) OR by
  setting the CMAKE_PREFIX_PATH environment variable (e.g.  export
  CMAKE_PREFIX_PATH=path_to_your_build_dir ..).


-- Configuring incomplete, errors occurred!
<<<<<<<<<<<<<<<<[ERROR END]>>>>>>>>>>>>>>

What else do I have to install to build it?