title: Dockerfile fails with llvm-config error for numba install
body: <p>My Dockerfile using a pypy base fails with FileNotFoundError: [Errno 2] No such file or directory: 'llvm-config' when installing llvmlite, a dependency of numba which is listed in my requirements.txt</p>
  
  <p>I tried to follow and update the instructions here
  <a href="https://stackoverflow.com/questions/34495356/python-numba-llvmlite-on-debian-8-i-cant-build-llvmlite">Python numba / llvmlite on Debian 8 - i can&#39;t build llvmlite</a></p>
  
  <p>My error in more detail:</p>
  
  <pre><code>Building wheels for collected packages: llvmlite
  Building wheel for llvmlite (setup.py): started
  Building wheel for llvmlite (setup.py): finished with status 'error'
  ERROR: Command errored out with exit status 1:
   command: /usr/local/bin/pypy3 -u -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/tmp/pip-install-ux49fegr/llvmlite/setup.py'"'"'; __file__='"'"'/tmp/pip-install-ux49fegr/llvmlite/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' bdist_wheel -d /tmp/pip-wheel-8s6wwump --python-tag pp371
     cwd: /tmp/pip-install-ux49fegr/llvmlite/
  Complete output (26 lines):
  running bdist_wheel
  /usr/local/bin/pypy3 /tmp/pip-install-ux49fegr/llvmlite/ffi/build.py
  LLVM version... Traceback (most recent call last):
    File "/tmp/pip-install-ux49fegr/llvmlite/ffi/build.py", line 105, in main_posix
      out = subprocess.check_output([llvm_config, '--version'])
    File "/usr/local/lib-python/3/subprocess.py", line 336, in check_output
      **kwargs).stdout
    File "/usr/local/lib-python/3/subprocess.py", line 403, in run
      with Popen(*popenargs, **kwargs) as process:
    File "/usr/local/lib-python/3/subprocess.py", line 722, in __init__
      restore_signals, start_new_session)
    File "/usr/local/lib-python/3/subprocess.py", line 1354, in _execute_child
      raise child_exception_type(errno_num, err_msg)
  FileNotFoundError: [Errno 2] No such file or directory: 'llvm-config'
  </code></pre>
  
  <p>I don't want the heavy weight of a conda installation. Is there a way to achieve a numba install for pypy without it?</p>
  
  <pre><code>FROM pypy:3.6-slim-stretch
  
  RUN apt-get update &amp;&amp; apt-get install -y gnupg wget software-properties-common
  RUN wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add - 15CF4D18AF4F7421
  RUN apt-add-repository "deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch-6.0 main"
  RUN apt-get update
  RUN apt-get -y install cython python-llvm build-essential libedit-dev
  RUN apt-get -y install libllvm6.0 llvm-6.0-dev llvm-dev
  
  RUN pip install enum34
  ENV LLVM_CONFIG=/usr/lib/llvm-6.0-dev/bin/llvm-config pip install llvmlite
  ENV LLVM_CONFIG=/usr/lib/llvm-6.0-dev/bin/llvm-config pip install numba
  # ENV LD_LIBRARY_PATH /usr/lib/llvm-6.0-dev/lib/
  
  #... other stuff
  
  RUN apt-get clean &amp;&amp; apt-get -y update
  RUN apt-get -y install python3-dev \
      &amp;&amp; apt-get -y install build-essential
  
  # Add requirements
  COPY requirements.txt /tmp/
  
  # Install sphinx first as it does not work inside requirements
  RUN pip install -U pip &amp;&amp; pip install -U sphinx &amp;&amp; pip install numpy &amp;&amp; pip install cython &amp;&amp;  \
    pip install -r /tmp/requirements.txt
  </code></pre>
  
  <p>I expect a clean build of the docker image with numba on pypy</p>