gnuradio compilation and also gr-air-modes issue

[address@hidden]

Yes I know this list is specifically for gnuradio. I just compiled
3.9.0.4 from source (github) on opensuse 15.2 and all went well. When I
ran the "make test" it seemed a bit slow then I realized I forgot to
specify the number of CPUs (the j option). Doing a "make clean" then
the properly flaged make the compilation took way longer. Just an
observation but very interesting. Next time I do a build I will save
the single CPU results from the 2cpu test for comparison.

Regarding compilation of code in general (not specific to gnuradio) I
have noticed with gcc10 a number of compilations bomb due to changes in
the compiler. Thus far I have been able to edit my way (change
compiler flags) out of the problem using tips found on the internet.
Just something to be on the lookout for.

Now regarding gr-air-modes I did file an "issue" on github but I
figured I would run the error past the hive because maybe it is another
fix that can been done with editing. 

Here is the error:

[ 11%] Building CXX object lib/CMakeFiles/air_modes.dir/preamble_impl.cc.o
/usr/local/src/gr-air-modes/lib/preamble_impl.cc: In static member function 
‘static gr::air_modes::preamble::sptr gr::air_modes::preamble::make(float, 
float)’:
/usr/local/src/gr-air-modes/lib/preamble_impl.cc:38:38: error: could not 
convert ‘gnuradio::get_initial_sptr(T*) [with T = 
gr::air_modes::preamble_impl]()’ from 
‘std::shared_ptr<gr::air_modes::preamble_impl>’ to 
‘gr::air_modes::preamble::sptr’ {aka 
‘boost::shared_ptr<gr::air_modes::preamble>’}
   38 |     return gnuradio::get_initial_sptr(new 
air_modes::preamble_impl(channel_rate, threshold_db));
      |            
~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      |                                      |
      |                                      
std::shared_ptr<gr::air_modes::preamble_impl>
make[2]: *** [lib/CMakeFiles/air_modes.dir/build.make:80: 
lib/CMakeFiles/air_modes.dir/preamble_impl.cc.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:286: lib/CMakeFiles/air_modes.dir/all] Error 
2
make: *** [Makefile:158: all] Error 2