Build error (macOS 10.15 Catalina)

I tried to build, but it gives an error at the end:



```

MACOS Installation from source

 ------------------------

 brew install gr-osmosdr

 brew install gnuradio

 brew install cmake

 brew install qt





$ git clone https://github.com/csete/gqrx.git gqrx.git

$ cd gqrx.git

$ mkdir build

$ cd build

$ cmake ..

$ make

```



error:



```

[ 90%] Building CXX object src/CMakeFiles/gqrx.dir/receivers/nbrx.cpp.o

[ 92%] Building CXX object src/CMakeFiles/gqrx.dir/receivers/receiver_base.cpp.o

[ 93%] Building CXX object src/CMakeFiles/gqrx.dir/receivers/wfmrx.cpp.o

[ 94%] Building CXX object src/CMakeFiles/gqrx.dir/portaudio/device_list.cpp.o

[ 96%] Building CXX object src/CMakeFiles/gqrx.dir/portaudio/portaudio_sink.cpp.o

[ 97%] Building CXX object src/CMakeFiles/gqrx.dir/qrc_icons.cpp.o

[ 98%] Building CXX object src/CMakeFiles/gqrx.dir/qrc_textfiles.cpp.o

[100%] Linking CXX executable gqrx

Undefined symbols for architecture x86_64:

  "_volk_32f_log2_32f", referenced from:

      MainWindow::iqFftTimeout() in mainwindow.cpp.o

  "_volk_32f_s32f_multiply_32f", referenced from:

      MainWindow::iqFftTimeout() in mainwindow.cpp.o

  "_volk_32fc_magnitude_squared_32f", referenced from:

      MainWindow::iqFftTimeout() in mainwindow.cpp.o

ld: symbol(s) not found for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

make[2]: *** [src/gqrx] Error 1

make[1]: *** [src/CMakeFiles/gqrx.dir/all] Error 2

make: *** [all] Error 2

Apple@iMac-Apple build % 

```



**How to fix it?**

[]