cl: instr funcAddr support typec funclit

cl/_testrt/funcaddr/in.go

@@ -0,0 +1,24 @@
+package main
+
+import (
+	"unsafe"
+
+	"github.com/goplus/llgo/c"
+)
+
+//llgo:type C
+type Add func(int, int) int
+
+func add(a, b int) int {
+	return a + b
+}
+
+func main() {
+	var fn Add = add
+	var myfn Add = func(a, b int) int {
+		return a + b
+	}
+	println(c.Func(add) == c.Func(fn))
+	println(c.Func(fn) == *(*unsafe.Pointer)(unsafe.Pointer(&fn)))
+	println(c.Func(myfn) == *(*unsafe.Pointer)(unsafe.Pointer(&myfn)))
+}