title: Yocto: Not able to building scikit-learn on yocto build system
body: <p>I installed numpy and scipy using yocto (warrior), but when I added the scikit-learn recipe, it is not able to find the numpy recipe.</p>
  
  <p>The recipe looks like this:</p>
  
  <pre><code>SUMMARY = "A set of python modules for machine learning and data mining"
  HOMEPAGE = "http://scikit-learn.org"
  # WARNING: the following LICENSE and LIC_FILES_CHKSUM values are best guesses - it is
  # your responsibility to verify that the values are complete and correct.
  #
  # The following license files were not able to be identified and are
  # represented as "Unknown" below, you will need to check them yourself:
  #   COPYING
  LICENSE = "new-BSD"
  LIC_FILES_CHKSUM = "file://COPYING;md5=5f6fa516b7dec5faf1c6031236caebce"
  
  SRC_URI = "https://files.pythonhosted.org/packages/18/28/5a48b00599b476875415b97bdfdb3849bafb31183c1d785501dbc8a77aa2/scikit-learn-${PV}.tar.gz"
  SRC_URI[md5sum] = "dab189dd5556ae59f7a1efce9c86c002"
  SRC_URI[sha256sum] = "51ee25330fc244107588545c70e2f3570cfc4017cff09eed69d6e1d82a212b7d"
  
  S = "${WORKDIR}/scikit-learn-${PV}"
  
  inherit setuptools3
  
  # WARNING: the following rdepends are determined through basic analysis of the
  # python sources, and might not be 100% accurate.
  RDEPENDS_${PN} += "python3-compression python3-core python3-crypt python3-difflib python3-distutils python3-io python3-json python3-logging python3-math python3-misc python3-numbers python3-pickle python3-pkgutil python3-pprint python3-shell python3-threading python3-unittest python3-numpy"
  </code></pre>
  
  <p>Log data follows:</p>
  
  <pre class="lang-none prettyprint-override"><code>DEBUG: Executing python function externalsrc_compile_prefunc
  NOTE: python3-scikit-learn: compiling from external source tree /home/test/build/workspace/sources/python3-scikit-learn
  DEBUG: Python function externalsrc_compile_prefunc finished
  DEBUG: Executing shell function do_compile
  Partial import of sklearn during the build process.
  Traceback (most recent call last):
  File "setup.py", line 195, in check_package_status
  module = importlib.import_module(package)
  File "/home/test/build/tmp/work/armv7vet2-neon-phytec-linux-gnueabi/python3-scikit-learn/0.22.1-r0/recipe-sysroot-native/usr/lib/python3.7/importlib/__init__.py", line 127, in import_module
  return _bootstrap._gcd_import(name[level:], package, level)
  File "&lt;frozen importlib._bootstrap&gt;", line 1006, in _gcd_import
  File "&lt;frozen importlib._bootstrap&gt;", line 983, in _find_and_load
  File "&lt;frozen importlib._bootstrap&gt;", line 965, in _find_and_load_unlocked
  ModuleNotFoundError: No module named 'numpy'
  Traceback (most recent call last):
  File "setup.py", line 303, in &lt;module&gt;
  setup_package()
  File "setup.py", line 291, in setup_package
  check_package_status('numpy', NUMPY_MIN_VERSION)
  File "setup.py", line 221, in check_package_status
  .format(package, req_str, instructions))
  ImportError: numpy is not installed.
  scikit-learn requires numpy &gt;= 1.11.0.
  Installation instructions are available on the scikit-learn website: http://scikit-learn.org/stable/install.html
  ERROR: 'python3 setup.py build ' execution failed.
  </code></pre>