protobuf-3.9.2-r0 has missing dependencies (seen on armhf)
ldd /usr/bin/protoc
/lib/ld-musl-armhf.so.1 (0xfff69000)
libprotoc.so.20 => /usr/lib/libprotoc.so.20 (0xff5f7000)
libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xff500000)
libgcc_s.so.1 => /usr/lib/libgcc_s.so.1 (0xff4e8000)
libc.musl-armv7.so.1 => /lib/ld-musl-armhf.so.1 (0xfff69000)
libprotobuf.so.20 => /usr/lib/libprotobuf.so.20 (0xff332000)
libz.so.1 => /lib/libz.so.1 (0xff312000)
Error relocating /usr/lib/libprotoc.so.20: _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev: symbol not found
Error relocating /usr/lib/libprotobuf.so.20: _ZNSt7__cxx1119basic_ostringstreamIcSt11char_traitsIcESaIcEEC1Ev: symbol not found