从github导入使用本机C代码的go软件包

I'm writing some code that needs access to a Cobra CLI object from another GitHub repo:

package main

import (
    "github.com/spf13/cobra/doc"
    "github.com/sylabs/singularity/cmd/singularity/cli"
    "log"
)

func main() {
    err := doc.GenReSTTree(cli.SingularityCmd, "./")
    if err != nil {
        log.Fatal(err)
    }
}

I also have the following version constraint:

[[constraint]]
  name = "github.com/sylabs/singularity"
  version = "3.0.3"

Now, when I go install, I get the error:

# github.com/TMiguelT/singularity-userdocs/vendor/github.com/sylabs/singularity/internal/pkg/runtime/engines/config/starter
vendor/github.com/sylabs/singularity/internal/pkg/runtime/engines/config/starter/starter.go:10:10: fatal error: starter.h: No such file or directory
 #include "starter.h"
          ^~~~~~~~~~~
compilation terminated.

So when I try to build my code, it tries to compile the singularity module and fails because it can't find some C code. This header file is located here in the repo I'm importing: https://github.com/sylabs/singularity/blob/v3.0.3/cmd/starter/c/starter.h

How can I make my go install aware of this, to ensure my project compiles?