title: Mac OS: Catalina: unable to execute 'gcc': No such file or directory
body: <p>MAC OS Catalina(10.15.1) seems to have created some problems for building code that uses gcc. I am trying to build a python application which is running into the following error.</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-html lang-html prettyprint-override"><code>Running setup.py install for pdftotext: started
      Running setup.py install for pdftotext: finished with status 'error'
      Complete output from command /usr/bin/python3 -u -c "import setuptools, tokenize;__file__='/tmp/pip-build-yzaiz97e/pdftotext/setup.py';f=getattr(tokenize, 'open', open)(__file__);code=f.read().replace('\r\n', '\n');f.close();exec(compile(code, __file__, 'exec'))" install --record /tmp/pip-67h0h5_9-record/install-record.txt --single-version-externally-managed --compile:
      WARNING: pkg-config not found--guessing at poppler version.
               If the build fails, install pkg-config and try again.
      /usr/lib64/python3.7/distutils/dist.py:274: UserWarning: Unknown distribution option: 'long_description_content_type'
        warnings.warn(msg)
      running install
      running build
      running build_ext
      building 'pdftotext' extension
      creating build
      creating build/temp.linux-x86_64-3.7
      gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -DPOPPLER_CPP_AT_LEAST_0_30_0=1 -I/usr/include/python3.7m -c pdftotext.cpp -o build/temp.linux-x86_64-3.7/pdftotext.o -Wall
      unable to execute 'gcc': No such file or directory
      error: command 'gcc' failed with exit status 1</code></pre>
  </div>
  </div>
  </p>
  
  <p>gcc is  definitely installed on the system but somehow not visible to pip installer.</p>
  
  <pre><code>which gcc
  
  /usr/bin/gcc
  
  
  packaging % gcc --version
  Configured with: --prefix=/Library/Developer/CommandLineTools/usr --with-gxx-include-dir=/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
  Apple clang version 11.0.0 (clang-1100.0.33.8)
  Target: x86_64-apple-darwin19.0.0
  Thread model: posix
  InstalledDir: /Library/Developer/CommandLineTools/usr/bin
  
  xcode-select --install                          
  xcode-select: error: command line tools are already installed, use "Software Update" to install updates
  </code></pre>
  
  <p>Any help to debug the issue would be appreciated.</p>