title: Conda-Build: Unsatisfiable dependencies for platform osx-64: {"torch[version='>=0.4']"}
body: <p>I'm new to building <code>conda</code> package. I've uploaded the package to <code>PyPI</code>, so I followed this documentation about <a href="https://conda.io/docs/user-guide/tutorials/build-pkgs-skeleton.html" rel="noreferrer">building conda from pip package</a>. It works when I tried building <code>pyinstrument</code> from <code>pip</code>, but I got the following error when I tried building my package. </p>
  
  <pre><code>conda_build.exceptions.DependencyNeedsBuildingError: Unsatisfiable dependencies for platform osx-64: {"torch[version='&gt;=0.4']"}
  </code></pre>
  
  <p>I found a similar issue <a href="https://stackoverflow.com/questions/46412980/conda-build-creating-a-conda-package-fails-on-dependencies-for-platform-win-64">here</a>, but adding channel didn't fix my issue since <code>pytorch</code> exists in default channel. </p>
  
  <p>Here is my <code>meta.yml</code> file: </p>
  
  <pre><code>{% set name = "scvi" %}
  {% set version = "0.1.2" %}
  {% set file_ext = "tar.gz" %}
  {% set hash_type = "sha256" %}
  {% set hash_value = "ca87155662d85605f86c5e86b7b9f64d881b882177b9642fff8f0ea215c6cb1a" %}
  
  package:
    name: '{{ name|lower }}'
    version: '{{ version }}'
  
  source:
    fn: '{{ name }}-{{ version }}.{{ file_ext }}'
    url: https://pypi.io/packages/source/{{ name[0] }}/{{ name }}/{{ name }}-{{ version }}.{{ file_ext }}
    '{{ hash_type }}': '{{ hash_value }}'
  
  build:
    number: 0
    script: python setup.py install --single-version-externally-managed --record=record.txt
  
  requirements:
    run:
      - python 3.6
      - setuptools
      - numpy&gt;=1.0
      - torch&gt;=0.4
      - matplotlib&gt;=2.0
      - scikit-learn&gt;=0.18
      - scipy&gt;=1.0
      - h5py&gt;=2.8
      - pandas&gt;=0.2
      - loompy&gt;=2.0
  
  test:
    imports:
      - scvi
      - scvi.dataset
      - scvi.metrics
      - scvi.models
    requires:
      - pytest
  
  about:
    home: https://github.com/YosefLab/scVI
    license: MIT
    license_family: MIT
    license_file: 'LICENSE'
    summary: Single-cell Variational Inference
    description: Single-cell Variational Inference
    doc_url: https://scvi.readthedocs.io
    dev_url: https://github.com/YosefLab/scVI
  </code></pre>
  
  <p>Any possible solutions or suggestions on which direction I should look into would be very helpful. Thanks! </p>