Compile error: cannot use _Ctype_long(port) (type _Ctype_long) as type _Ctype_longlong in argument

[ganeshrvel]

I use macOS Catalina 10.15.6.
go version: go1.14.5 darwin/amd64

I cloned this repo to my local machine and when I try to compile the code it throws:

go build -v -o godart.so -buildmode=c-shared

Error:

runtime/cgo
_/Users/username/go_dart_ffi_example/dart_api_dl
# _/Users/username/go_dart_ffi_example/dart_api_dl
dart_api_dl/dart_api_dl.go:23:29: cannot use _Ctype_long(port) (type _Ctype_long) as type _Ctype_longlong in argument to _Cfunc_GoDart_PostCObject