[Buildroot] [git commit branch/2023.05.x] package/gnuradio: fix gnuradio python libraries for cross-compile

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=bf041313f95cfd3b592621c875d7dfdf5c7f4d86
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2023.05.x

By default, module libraries have a suffix based on cpython version + host
architecture: this is fine for a native compile when these libraries are used on
the same computer (or similar computers). But when target architecture is not
the same python is unable to find libraries due to the wrong suffix and produces
unclear errors messages:

# python3
Python 3.11.3 (main, Jun 19 2023, 14:15:44) [GCC 11.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> from gnuradio import blocks
Traceback (most recent call last):
  File "/home/xxx/buildroot/output/build/gnuradio-3.10.4.0/gr-blocks/python/blocks/__init__.py", line 18, in <module>
ModuleNotFoundError: No module named 'gnuradio.blocks.blocks_python'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/xxx/buildroot/output/build/gnuradio-3.10.4.0/gr-blocks/python/blocks/__init__.py", line 22, in <module>
ModuleNotFoundError: No module named 'gnuradio.blocks.blocks_python'
>>>

By adding _PYTHON_SYSCONFIGDATA_NAME="$(PKG_PYTHON_SYSCONFIGDATA_NAME)" at configure time, sysconfig will
return correct informations (target architecture) instead of host architecture.

Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou at trabucayre.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni at bootlin.com>
(cherry picked from commit e22b450692a6d02da43a453f24ec057bb5517422)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/gnuradio/gnuradio.mk | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/package/gnuradio/gnuradio.mk b/package/gnuradio/gnuradio.mk
index 1453b78493..8eb7778d99 100644
--- a/package/gnuradio/gnuradio.mk
+++ b/package/gnuradio/gnuradio.mk
@@ -119,6 +119,10 @@ GNURADIO_CONF_OPTS += -DENABLE_PYTHON=ON
 # mandatory to avoid pybind11 to overwrite variables provided
 # by gnuradio and buildroot
 GNURADIO_CONF_OPTS += -DPYBIND11_PYTHONLIBS_OVERWRITE=OFF
+# mandatory to avoid pybind11 to force libraries extensions
+# with a name based on host architecture
+GNURADIO_CONF_ENV += _PYTHON_SYSCONFIGDATA_NAME="$(PKG_PYTHON_SYSCONFIGDATA_NAME)" \
+	PYTHONPATH=$(PYTHON3_PATH)
 # mandatory to install python modules in site-packages and to use
 # correct path for python libraries
 GNURADIO_CONF_OPTS += -DGR_PYTHON_RELATIVE=ON \