[gjs/fix-msvc-gnome42] gi/arg-cache.cpp: Fix building on Visual Studio

[Chun-wei Fan <fanchunwei src gnome org>]

commit 0d0dce549611e2da966092b040d192e07bca3a66
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Jul 20 11:21:12 2022 +0800

    gi/arg-cache.cpp: Fix building on Visual Studio
    
    Marking the constructor for `Callback` as constexpr caused trouble for Visual
    Studio as the definition of `CallbackIn` rejected it as the SkipAll items
    are not marked as constexpr, so make the constructor for `Callback` non-
    constexpr to fix the build.

 gi/arg-cache.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gi/arg-cache.cpp b/gi/arg-cache.cpp
index df7cd1c67..017f17493 100644
--- a/gi/arg-cache.cpp
+++ b/gi/arg-cache.cpp
@@ -262,7 +262,7 @@ struct RegisteredInterface : BaseInfo {
 };
 
 struct Callback : Nullable, BaseInfo {
-    constexpr explicit Callback(GIInterfaceInfo* info)
+    explicit Callback(GIInterfaceInfo* info)
         : BaseInfo(info, GjsAutoTakeOwnership{}),
           m_scope(GI_SCOPE_TYPE_INVALID) {}