saving script with cpp instead py

Hello,

I can't save any script to run as cpp, because block that I'm using (gr-osmosdr) not support cpp. Searching I found this example, need to turn flag cpp and alo include cpp_template, means that I need to compile from the source, but than I realize that almost all hardware sink/wrappers and sources blocks inside gnuradio installed from package, don't offer also cpp support. 

Add C++ generation support in GRC to all blocks · Issue #2297 · gnuradio/gnuradio The checklists below indicate which blocks have C++ support in master. gr-analog 25/34 ✔️ analog_agc2_xx analog_agc3_xx analog_agc_xx analog_am_demod_cf analog_const_source_x analog_cpfsk_bc analog... github.com

Now I don't know if I need to turn this feature on the gnuradio level, when I'm compiling or just block per block, and if second option true, what would be correct procedure to include cpp saving script when compiling gr-osmosdr.

Robin