[gjs: 2/10] function: Mark accessor methods as const

[Philip Chimento <pchimento src gnome org>]

commit 6df163acfaf1a7f71138572fd310712cbc7bc62f
Author: Philip Chimento <philip chimento gmail com>
Date:   Fri Mar 12 11:37:03 2021 -0800

    function: Mark accessor methods as const

 gi/function.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gi/function.h b/gi/function.h
index 034c8d50..759a01dd 100644
--- a/gi/function.h
+++ b/gi/function.h
@@ -43,8 +43,8 @@ struct GjsCallbackTrampoline {
                           bool is_vfunc);
     ~GjsCallbackTrampoline();
 
-    constexpr GClosure* js_function() { return m_js_function; }
-    constexpr ffi_closure* closure() { return m_closure; }
+    constexpr GClosure* js_function() const { return m_js_function; }
+    constexpr ffi_closure* closure() const { return m_closure; }
 
     gatomicrefcount ref_count;