I have dowloaded METAL from its github page, by simply pressing "code" and "download ZIP". I then proceed to follow the instructions on the webpage.

I navigate to the directory containing the source files for METAL....

user@Users/user/Documents/METAL-master % ls
CMakeLists.txt  ChangeLog   LICENSE.twister README.md   examples    libsrc      metal       pdf     tests       version

... and paste in the commands from the github page.

mkdir build && cd build
cmake -DCMAKE_BUILD_TYPE=Release ..
make
make test
make install

.. this throws and error messages as such:

-- The C compiler identification is unknown
-- The CXX compiler identification is unknown
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc - broken
CMake Error at /Applications/CMake.app/Contents/share/cmake-3.17/Modules/CMakeTestCCompiler.cmake:60 (message):
  The C compiler

    "/usr/bin/cc"

  is not able to compile a simple test program.

  It fails with the following output:

    Change Dir: /Users/user/Documents/METAL-master/build/CMakeFiles/CMakeTmp

    Run Build Command(s):/usr/bin/make cmTC_823e4/fast && xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun





  CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
  CMakeLists.txt:8 (project)


-- Configuring incomplete, errors occurred!
See also "/Users/user/Documents/METAL-master/build/CMakeFiles/CMakeOutput.log".
See also "/Users/user/Documents/METAL-master/build/CMakeFiles/CMakeError.log".
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

how can I download METAL to perform my meta analysis?