Latest error on install

```
Undefined symbols for architecture x86_64:
"_protobuf_c_message_free_unpacked", referenced from:
_vector_tile__tile__free_unpacked in vector_tile.pb-c.o
_data__free_unpacked in geobuf.pb-c.o
"_protobuf_c_message_get_packed_size", referenced from:
_vector_tile__tile__get_packed_size in vector_tile.pb-c.o
_data__get_packed_size in geobuf.pb-c.o
"_protobuf_c_message_pack", referenced from:
_vector_tile__tile__pack in vector_tile.pb-c.o
_data__pack in geobuf.pb-c.o
"_protobuf_c_message_pack_to_buffer", referenced from:
_vector_tile__tile__pack_to_buffer in vector_tile.pb-c.o
_data__pack_to_buffer in geobuf.pb-c.o
"_protobuf_c_message_unpack", referenced from:
_vector_tile__tile__unpack in vector_tile.pb-c.o
_data__unpack in geobuf.pb-c.o
"_protobuf_c_version", referenced from:
_postgis_libprotobuf_version in postgis_libprotobuf.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make[1]: *** [postgis-2.5.so] Error 1
make: *** [all] Error 1
```

Start by reviewing the build and install configuration that links vector_tile.pb-c.o, geobuf.pb-c.o, and postgis_libprotobuf.o. Trace where the protobuf-c symbols should be provided, then verify the fix by rerunning the x86_64 installation until postgis-2.5.so links successfully.

Written by the indexing model from the issue text.