#spec.objects extension always ".o"

[ghost]

when I compile this on windows
{port_specs, [
{"priv/enif_protobuf.dll", [
"c_src/enif_protobuf.c",
"c_src/ep_cache.c",
"c_src/ep_decoder.c",
"c_src/ep_encoder.c",
"c_src/ep_node.c"
]}
]}.
I find that "pc_port_specs:get_port_spec/3" always replace extension to ".o", then I get this(DEBUG=1)
sh(cmd /q /c link.exe c_src/enif_protobuf.o c_src/ep_cache.o c_src/ep_decoder.o c_src/ep_encoder.o c_src/ep_node.o /DLL

in fact, "pc_compilation:compile_each/5" create ".obj" file

so, i think "pc_port_specs:get_port_spec/3" shoule use "pc_port_specs:object_file_ext/0" to decide ext too