CMake - clang++ is not able compile a simple test program Ubuntu 18.04

Question

I am trying to install PotreeConverte, and instructions for that are:

sudo apt-get install python-software-properties git
sudo apt-get install build-essential cmake g++
sudo apt-get install libboost-all-dev
sudo apt-get install cmake-curses-gui
sudo apt-get install gcc
--LAStools:
git clone https://github.com/m-schuetz/LAStools.git
cd LAStools/LASzip
mkdir build && cd build
**cmake -DCMAKE_BUILD_TYPE=Release ..**
make
etc..

Anyway, I am stuck at the installation of LAStools. When I run:

cmake -DCMAKE_BUILD_TYPE=Release ..

I get the output:

-- The CXX compiler identification is Clang 6.0.0
-- Check for working CXX compiler: /usr/bin/clang++
-- Check for working CXX compiler: /usr/bin/clang++ -- broken
CMake Error at /usr/share/cmake-3.10/Modules/CMakeTestCXXCompiler.cmake:45 (message):
 The C++ compiler

"/usr/bin/clang++"

  is not able to compile a simple test program.

 It fails with the following output:

Change Dir: /home/user/LAStools/LASzip/build/CMakeFiles/CMakeTmp

Run Build Command:"/usr/bin/make" "cmTC_4b938/fast"
/usr/bin/make -f CMakeFiles/cmTC_4b938.dir/build.make 
CMakeFiles/cmTC_4b938.dir/build
make[1]: Entering directory '/home/user/LAStools/LASzip/build/CMakeFiles/CMakeTmp'
Building CXX object 
CMakeFiles/cmTC_4b938.dir/testCXXCompiler.cxx.o
/usr/bin/clang++     -o 
CMakeFiles/cmTC_4b938.dir/testCXXCompiler.cxx.o -c /home/user/LAStools/LASzip/build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
Linking CXX executable cmTC_4b938
/usr/bin/cmake -E cmake_link_script 
CMakeFiles/cmTC_4b938.dir/link.txt --verbose=1
/usr/bin/clang++       -rdynamic 
CMakeFiles/cmTC_4b938.dir/testCXXCompiler.cxx.o  -o cmTC_4b938 
/usr/bin/ld: cannot find -lstdc++
clang: error: linker command failed with exit code 1 (use -v to see invocation)
CMakeFiles/cmTC_4b938.dir/build.make:97: recipe for target 'cmTC_4b938' failed
make[1]: *** [cmTC_4b938] Error 1
make[1]: Leaving directory '/home/user/LAStools/LASzip/build/CMakeFiles/CMakeTmp'
Makefile:126: recipe for target 'cmTC_4b938/fast' failed
make: *** [cmTC_4b938/fast] Error 2

CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:3 (project)

etc..

I checked and I have libstdc++.so and libstdc++.so.6 Also, I have seen this question and answers, but it didn't help me. On this picture are versions of the compiler which I have: