build.txt

$ CGO_ENABLED=1\
  CC=arm-linux-androideabi-gcc\
  GOOS=android\
  GOARCH=arm\
  GOARM=7\
  go buid -build-mode=pie hellocgo.go

hellocgo.go

package main

import "unsafe"

/*
#include <stdio.h>
#include <stdlib.h>

void hello(char *s) {
	printf("Hello, %s\n", s);
}
*/
import "C"

func main() {
	str := C.CString("Droid Kaigi")
	C.hello(str)
	C.free(unsafe.Pointer(str))
}