title: Failed building wheel for qdldl (when installing cvxpy)
body: <p>Independent whether I install using pip or from source, whether I use python2 or python3 I can't install cvxpy. I've tried now over four hours and I still fail.  The github pages of cvxpy or qdldl wouldn't give me any solution. I installed the packages which led to other errors with no success. Any hints are appreciated.</p>
  <pre><code>user@ion:~ $ sudo pip install cvxpy
  
  Looking in indexes: https://pypi.org/simple, https://www.piwheels.org/simple
  Collecting cvxpy
    Using cached https://files.pythonhosted.org/packages/11/d0/d900870dc2d02ea74961b90c353666c6528a33ea61a10aa59a0d5574ae59/cvxpy-1.0.31.tar.gz
    Installing build dependencies ... done
  Collecting osqp&gt;=0.4.1 (from cvxpy)
    Using cached https://files.pythonhosted.org/packages/c0/90/4cf48c200a89e46bcad87e12469ee36fc03d0c3f16b703b747e8c4bf618e/osqp-0.6.2.post0.tar.gz
    Installing build dependencies ... done
      Complete output from command python setup.py egg_info:
        Failed building wheel for qdldl
      ERROR: Failed to build one or more wheels
      Disabling LONG
      Remove long integers for numpy compatibility. See:
       - https://github.com/numpy/numpy/issues/5906
       - https://github.com/ContinuumIO/anaconda-issues/issues/3823
      You can reenable long integers by passing: --osqp --long argument.
      
      Traceback (most recent call last):
        File &quot;&lt;string&gt;&quot;, line 1, in &lt;module&gt;
        File &quot;/tmp/pip-install-zEueiK/osqp/setup.py&quot;, line 276, in &lt;module&gt;
          ext_modules=[_osqp])
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/setuptools/__init__.py&quot;, line 161, in setup
          _install_setup_requires(attrs)
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/setuptools/__init__.py&quot;, line 156, in _install_setup_requires
          dist.fetch_build_eggs(dist.setup_requires)
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/setuptools/dist.py&quot;, line 721, in fetch_build_eggs
          replace_conflicting=True,
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/pkg_resources/__init__.py&quot;, line 782, in resolve
          replace_conflicting=replace_conflicting
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/pkg_resources/__init__.py&quot;, line 1065, in best_match
          return self.obtain(req, installer)
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/pkg_resources/__init__.py&quot;, line 1077, in obtain
          return installer(requirement)
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/setuptools/dist.py&quot;, line 777, in fetch_build_egg
          return fetch_build_egg(self, req)
        File &quot;/tmp/pip-build-env-vbB_nz/lib/python2.7/site-packages/setuptools/installer.py&quot;, line 130, in fetch_build_egg
          raise DistutilsError(str(e))
      distutils.errors.DistutilsError: Command '['/usr/bin/python', '-m', 'pip', '--disable-pip-version-check', 'wheel', '--no-deps', '-w', '/tmp/tmpsvIroT', '--quiet', 'qdldl']' returned non-zero exit status 1
      
      ----------------------------------------
  Command &quot;python setup.py egg_info&quot; failed with error code 1 in /tmp/pip-install-zEueiK/osqp/
  </code></pre>
  <p>Or here installing from sources in python 3</p>
  <pre><code>user@ion:~/osqp-python $ sudo python3 setup.py install 
  no previously-included directories found matching 'tests/__pycache__/'
  no previously-included directories found matching 'c/build/'
  no previously-included directories found matching 'c/qdldl/build'
  -- The C compiler identification is GNU 8.3.0
  -- The CXX compiler identification is GNU 8.3.0
  -- Check for working C compiler: /usr/bin/cc
  -- Check for working C compiler: /usr/bin/cc -- works
  -- Detecting C compiler ABI info
  -- Detecting C compiler ABI info - done
  -- Detecting C compile features
  -- Detecting C compile features - done
  -- Check for working CXX compiler: /usr/bin/c++
  -- Check for working CXX compiler: /usr/bin/c++ -- works
  -- Detecting CXX compiler ABI info
  -- Detecting CXX compiler ABI info - done
  -- Detecting CXX compile features
  -- Detecting CXX compile features - done
  -- Floats are OFF
  -- Disabling long integers (64bit) on 32bit machine
  -- Long integers (64bit) are OFF
  -- Configuring done
  -- Generating done
  -- Build files have been written to: /tmp/easy_install-zqykb8_c/qdldl-0.1.5.post0/c/build
  Scanning dependencies of target qdldlobject
  [  6%] Building C object qdldl/CMakeFiles/qdldlobject.dir/src/qdldl.c.o
  [  6%] Built target qdldlobject
  Scanning dependencies of target qdldlamd
  [ 13%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_1.c.o
  [ 20%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_2.c.o
  [ 26%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_aat.c.o
  [ 33%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_control.c.o
  [ 40%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_defaults.c.o
  [ 46%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_info.c.o
  [ 53%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_order.c.o
  [ 60%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_post_tree.c.o
  [ 66%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_postorder.c.o
  [ 73%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_preprocess.c.o
  [ 80%] Building C object CMakeFiles/qdldlamd.dir/amd/src/amd_valid.c.o
  [ 86%] Building C object CMakeFiles/qdldlamd.dir/amd/src/SuiteSparse_config.c.o
  [ 93%] Building C object CMakeFiles/qdldlamd.dir/amd/src/perm.c.o
  [100%] Linking C static library out/libqdldlamd.a
  [100%] Built target qdldlamd
  cpp/qdldl.cpp: In constructor ‘qdldl::Solver::Solver(QDLDL_int, QDLDL_int*, QDLDL_int*, QDLDL_float*)’:
  cpp/qdldl.cpp:34:41: error: cannot convert ‘QDLDL_int*’ {aka ‘int*’} to ‘const long long int*’
    QDLDL_int amd_status = amd_l_order(nx, Ap, Ai, P, NULL, NULL);
                                           ^~
  In file included from cpp/qdldl.hpp:3,
                   from cpp/qdldl.cpp:1:
  c/amd/include/amd.h:63:28: note:   initializing argument 2 of ‘long long int amd_l_order(long long int, const long long int*, const long long int*, long long int*, c_float*, c_float*)’
       const SuiteSparse_long Ap [ ],
       ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
  Traceback (most recent call last):
    File &quot;/usr/lib/python3.7/distutils/unixccompiler.py&quot;, line 118, in _compile
      extra_postargs)
    File &quot;/usr/lib/python3.7/distutils/ccompiler.py&quot;, line 909, in spawn
      spawn(cmd, dry_run=self.dry_run)
    File &quot;/usr/lib/python3.7/distutils/spawn.py&quot;, line 36, in spawn
      _spawn_posix(cmd, search_path, dry_run=dry_run)
    File &quot;/usr/lib/python3.7/distutils/spawn.py&quot;, line 159, in _spawn_posix
      % (cmd, exit_status))
  distutils.errors.DistutilsExecError: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File &quot;/usr/lib/python3.7/distutils/core.py&quot;, line 148, in setup
      dist.run_commands()
    File &quot;/usr/lib/python3.7/distutils/dist.py&quot;, line 966, in run_commands
      self.run_command(cmd)
    File &quot;/usr/lib/python3.7/distutils/dist.py&quot;, line 985, in run_command
      cmd_obj.run()
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/bdist_egg.py&quot;, line 172, in run
      cmd = self.call_command('install_lib', warn_dir=0)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/bdist_egg.py&quot;, line 158, in call_command
      self.run_command(cmdname)
    File &quot;/usr/lib/python3.7/distutils/cmd.py&quot;, line 313, in run_command
      self.distribution.run_command(command)
    File &quot;/usr/lib/python3.7/distutils/dist.py&quot;, line 985, in run_command
      cmd_obj.run()
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/install_lib.py&quot;, line 24, in run
      self.build()
    File &quot;/usr/lib/python3.7/distutils/command/install_lib.py&quot;, line 109, in build
      self.run_command('build_ext')
    File &quot;/usr/lib/python3.7/distutils/cmd.py&quot;, line 313, in run_command
      self.distribution.run_command(command)
    File &quot;/usr/lib/python3.7/distutils/dist.py&quot;, line 985, in run_command
      cmd_obj.run()
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/build_ext.py&quot;, line 78, in run
      _build_ext.run(self)
    File &quot;/usr/lib/python3.7/distutils/command/build_ext.py&quot;, line 340, in run
      self.build_extensions()
    File &quot;/tmp/easy_install-zqykb8_c/qdldl-0.1.5.post0/setup.py&quot;, line 91, in build_extensions
      # Interface files
    File &quot;/usr/lib/python3.7/distutils/command/build_ext.py&quot;, line 449, in build_extensions
      self._build_extensions_serial()
    File &quot;/usr/lib/python3.7/distutils/command/build_ext.py&quot;, line 474, in _build_extensions_serial
      self.build_extension(ext)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/build_ext.py&quot;, line 199, in build_extension
      _build_ext.build_extension(self, ext)
    File &quot;/usr/lib/python3.7/distutils/command/build_ext.py&quot;, line 534, in build_extension
      depends=ext.depends)
    File &quot;/usr/lib/python3.7/distutils/ccompiler.py&quot;, line 574, in compile
      self._compile(obj, src, ext, cc_args, extra_postargs, pp_opts)
    File &quot;/usr/lib/python3.7/distutils/unixccompiler.py&quot;, line 120, in _compile
      raise CompileError(msg)
  distutils.errors.CompileError: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 154, in save_modules
      yield saved
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 195, in setup_context
      yield
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 250, in run_setup
      _execfile(setup_script, ns)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 45, in _execfile
      exec(code, globals, locals)
    File &quot;/tmp/easy_install-zqykb8_c/qdldl-0.1.5.post0/setup.py&quot;, line 124, in &lt;module&gt;
      # External libraries
    File &quot;/usr/lib/python3/dist-packages/setuptools/__init__.py&quot;, line 145, in setup
      return distutils.core.setup(**attrs)
    File &quot;/usr/lib/python3.7/distutils/core.py&quot;, line 163, in setup
      raise SystemExit(&quot;error: &quot; + str(msg))
  SystemExit: error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 1169, in run_setup
      run_setup(setup_script, args)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 253, in run_setup
      raise
    File &quot;/usr/lib/python3.7/contextlib.py&quot;, line 130, in __exit__
      self.gen.throw(type, value, traceback)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 195, in setup_context
      yield
    File &quot;/usr/lib/python3.7/contextlib.py&quot;, line 130, in __exit__
      self.gen.throw(type, value, traceback)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 166, in save_modules
      saved_exc.resume()
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 141, in resume
      six.reraise(type, exc, self._tb)
    File &quot;/usr/lib/python3/dist-packages/setuptools/_vendor/six.py&quot;, line 685, in reraise
      raise value.with_traceback(tb)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 154, in save_modules
      yield saved
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 195, in setup_context
      yield
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 250, in run_setup
      _execfile(setup_script, ns)
    File &quot;/usr/lib/python3/dist-packages/setuptools/sandbox.py&quot;, line 45, in _execfile
      exec(code, globals, locals)
    File &quot;/tmp/easy_install-zqykb8_c/qdldl-0.1.5.post0/setup.py&quot;, line 124, in &lt;module&gt;
      # External libraries
    File &quot;/usr/lib/python3/dist-packages/setuptools/__init__.py&quot;, line 145, in setup
      return distutils.core.setup(**attrs)
    File &quot;/usr/lib/python3.7/distutils/core.py&quot;, line 163, in setup
      raise SystemExit(&quot;error: &quot; + str(msg))
  SystemExit: error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File &quot;setup.py&quot;, line 276, in &lt;module&gt;
      ext_modules=[_osqp])
    File &quot;/usr/lib/python3/dist-packages/setuptools/__init__.py&quot;, line 144, in setup
      _install_setup_requires(attrs)
    File &quot;/usr/lib/python3/dist-packages/setuptools/__init__.py&quot;, line 139, in _install_setup_requires
      dist.fetch_build_eggs(dist.setup_requires)
    File &quot;/usr/lib/python3/dist-packages/setuptools/dist.py&quot;, line 724, in fetch_build_eggs
      replace_conflicting=True,
    File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 782, in resolve
      replace_conflicting=replace_conflicting
    File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 1065, in best_match
      return self.obtain(req, installer)
    File &quot;/usr/lib/python3/dist-packages/pkg_resources/__init__.py&quot;, line 1077, in obtain
      return installer(requirement)
    File &quot;/usr/lib/python3/dist-packages/setuptools/dist.py&quot;, line 791, in fetch_build_egg
      return cmd.easy_install(req)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 704, in easy_install
      return self.install_item(spec, dist.location, tmpdir, deps)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 730, in install_item
      dists = self.install_eggs(spec, download, tmpdir)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 915, in install_eggs
      return self.build_and_install(setup_script, setup_base)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 1183, in build_and_install
      self.run_setup(setup_script, setup_base, args)
    File &quot;/usr/lib/python3/dist-packages/setuptools/command/easy_install.py&quot;, line 1171, in run_setup
      raise DistutilsError(&quot;Setup script exited with %s&quot; % (v.args[0],))
  distutils.errors.DistutilsError: Setup script exited with error: command 'arm-linux-gnueabihf-gcc' failed with exit status 1
  </code></pre>