Hi all:

I'm trying to build the latest gr-osmosdr package from the gr3.8 branch, but I'm
seeing some unusual errors, and I'm not quite sure what the deal is.

I'll note the following:
- I had errors related to existing python2 packages, so I tried building with Python3.
  I'd be less than surprised if someone says that this is the cause of the issues, but
  personally, I'd like to roll with the Py3 products from now on, what with Py2 being EOL…
- OS is Arch.

My cmake command was:
```
  cmake \
    -DCMAKE_BUILD_TYPE=Release \
    -DPYTHON_EXECUTABLE=$(which python3) \
    -DPYTHON_INCLUDE_DIR=$(echo /usr/include/python3*) \
    -DPYTHON_LIBRARY=$(echo /usr/lib/libpython3.*.so) \
    -DENABLE_DOXYGEN=1 \
    -DCMAKE_INSTALL_PREFIX=/usr ../
```


Output from cmake:

```
-- ######################################################
-- # Gnuradio enabled components                         
-- ######################################################
--   * Python support
--   * sysmocom OsmoSDR
--   * IQ File Source & Sink
--   * Osmocom RTLSDR
--   * RTLSDR TCP Client
--   * Ettus USRP Devices
--   * Osmocom MiriSDR
--   * HackRF & rad1o Badge
--   * nuand bladeRF
--   * RFSPACE Receivers
--   * AIRSPY Receiver
--   * SoapySDR support
--   * Red Pitaya SDR
--
-- ######################################################
-- # Gnuradio disabled components                       
-- ######################################################
--   * Osmocom IQ Imbalance Correction
--   * AIRSPY HF+ Receiver
--   * FreeSRP support
--
-- Building for version: 0.2.0.0 / 0.2.0
-- Using install prefix: /usr
-- Configuring done
CMake Error at lib/CMakeLists.txt:43 (add_library):
  Target "gnuradio-osmosdr" links to target "gnuradio::filter" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


CMake Error at /usr/lib64/cmake/gnuradio/UseSWIG.cmake:573 (add_library):
  Target "osmosdr_swig" links to target "gnuradio::filter" but the target was
  not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
Call Stack (most recent call first):
  /usr/lib64/cmake/gnuradio/GrSwig.cmake:133 (swig_add_library)
  swig/CMakeLists.txt:42 (GR_SWIG_MAKE)


CMake Error at lib/CMakeLists.txt:43 (add_library):
  Target "gnuradio-osmosdr" links to target "gnuradio::filter" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?


-- Generating done
CMake Generate step failed.  Build files cannot be regenerated correctly.
```

Any feedback would be appreciated.
Thanks,

--
Tom Swartz