golang: Properly build the go hello world.

My toolchain path can be different than your
toolchain path.

Also take care of making the module a C module
and exporting proper GoMain() as used by OSv.

Signed-off-by: Benoît Canet <benoit@scylladb.com>
Message-Id: <1476973368-20687-1-git-send-email-benoit@scylladb.com>

golang-example/Makefile

@@ -3,7 +3,7 @@ module: hello
 	echo '/hello: $${MODULE_DIR}/hello' > usr.manifest
 
 hello: hello.go
-	/usr/lib/golang/bin/go build -buildmode=c-shared hello.go
+	go build -buildmode=c-shared hello.go
 
 clean:
 	rm -f hello usr.manifest

golang-example/hello.go

@@ -3,9 +3,14 @@ package main
 import (
         "runtime"
         "fmt"
+	"C"
 )
 
 func main() {
+}
+
+//export GoMain
+func GoMain() {
 	fmt.Println("Hello, 世界");
 	fmt.Println("Go version:", runtime.Version());
 }