could not determine kind of name for C.kodo

[tools@steinwurf-124 kodogo]$ ./compile 
go build: when using gccgo toolchain, please pass linker flags using -gccgoflags, not -ldflags
# command-line-arguments
could not determine kind of name for C.kodo

/*
#cgo LDFLAGS: -Llibkodoc.so
#include "kodoc.h"
*/
import "C"

import "unsafe"

type Factory C.kodo_factory_t
type Coder C.kodo_coder_t

//------------------------------------------------------------------
// Factory API
//------------------------------------------------------------------

func deleteFactory(factory Factory) {
    C.kodo_delete_factory(factory)
}

func newEncoderFactory(code_type int32, finite_field int32,
    max_symbols uint32, max_symbol_size uint32) Factory {
    return C.kodo_new_encoder_factory(code_type, finite_field,
                                      max_symbols, max_symbol_size)
}