[Buildroot] [git commit] opencv3: fix Python module build for Python 3.x

[Peter Korsgaard]

>>>>> "Thomas" == Thomas Petazzoni <thomas.petazzoni at bootlin.com> writes:

 > commit: https://git.buildroot.net/buildroot/commit/?id=8ba80282c3bb580c6a45ea114e70acac98fe1690
 > branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/master

 > When the OpenCV3 Python support is enabled with Python 3.x, it builds
 > properly, and the resulting .so file is built for the target
 > architecture, but its name is wrong:

 >   output/target/usr/lib/python3.6/site-packages/cv2.cpython-36m-x86_64-linux-gnu.so

 > This prevents Python 3.x from importing the module:

 >>>> import cv2
 > Traceback (most recent call last):
 >   File "<stdin>", line 1, in <module>
 > ModuleNotFoundError: No module named 'cv2'

 > In order to fix this, we simply need to pass PKG_PYTHON_DISTUTILS_ENV
 > in the environment. The Python module then gets named:

 >   output/target/usr/lib/python3.6/site-packages/cv2.cpython-36m-arm-linux-gnueabi.so

 > And can be imported properly:

 >>>> import cv2
 >>>> 

 > This solution was suggested by Arnout Vandecappelle in
 > https://stackoverflow.com/questions/49059035/buildroot-opencv3-python-package-builds-for-the-wrong-target.

 > With Python 2.x, the module is named just cv2.so so this problem isn't
 > visible. However, for consistency, we also pass
 > PKG_PYTHON_DISTUTILS_ENV when building against Python 2.x, by putting
 > the OPENCV3_CONF_ENV assignment inside the
 > BR2_PACKAGE_OPENCV3_LIB_PYTHON condition, but outside the
 > BR2_PACKAGE_PYTHON3/BR2_PACKAGE_PYTHON condition.

 > Signed-off-by: Sasha Shyrokov <alexander-shyrokov at idexx.com>
 > [Thomas: extend the commit log, apply the solution to Python 2.x.]
 > Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>

Committed to 2017.02.x, thanks.

-- 
Bye, Peter Korsgaard