neco: fix

c/neco/_demo/cgen/cgen.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	_ "unsafe"
+
+	_ "github.com/goplus/llgo/c"
+)
+
+const (
+	LLGoFiles   = "_c/gen.c; ../../_wrap/neco.c"
+	LLGoPackage = "link"
+)
+
+func main() {
+	runMain()
+}
+
+//go:linkname runMain C.run_main
+func runMain() {}