FindProtobuf: protobof_generate_cpp() could come from either cmake or protocol buffers implementation.
From 3.14 onwards the function protobuf_generate_cpp() appears to be deprecated in favour of protobuf_generate(). The old function is available if you add:
set(protobuf_MODULE_COMPATIBLE ON CACHE BOOL "")
This is not mentioned in the documentation on - https://cmake.org/cmake/help/v3.18/module/FindProtobuf.html The most useful source of information I found was stackoverflow:
https://stackoverflow.com/questions/52533396/cmake-cant-find-protobuf-protobuf-generate-cpp
The protobuf_generate() API is not documented.
Edited by Bruce Adams