compileValue ssa.Function fix: v.Pkg == nil: means auto generated function?

cl/_testrt/intgen/in.go

@@ -4,6 +4,15 @@ import (
 	"github.com/goplus/llgo/internal/runtime/c"
 )
 
+type generator struct {
+	val c.Int
+}
+
+func (g *generator) next() c.Int {
+	g.val++
+	return g.val
+}
+
 func genInts(n int, gen func() c.Int) []c.Int {
 	a := make([]c.Int, n)
 	for i := range a {
@@ -25,4 +34,8 @@ func main() {
 	for _, v := range b {
 		c.Printf(c.Str("%d\n"), v)
 	}
+	g := &generator{val: 1}
+	for _, v := range genInts(5, g.next) {
+		c.Printf(c.Str("%d\n"), v)
+	}
 }