[gtk+] gdk/gdkvulkancontext.c: Fix 32-bit Windows builds

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

commit 77e1d0c0c98d0df063c7925c00e2167e0cf841a3
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jun 5 22:17:12 2017 +0800

    gdk/gdkvulkancontext.c: Fix 32-bit Windows builds
    
    The callback function that is used by VkDebugReportCallbackCreateInfoEXT
    is decorated with VKAPI_CALL (which is __stdcall on Windows).  This is
    not detected on x64 Windows as __stdcall is not really meaningful on x64
    Windows, and VKAPI_CALL expands to nothing on non-Windows.
    
    As __stdcall functions are treated differently on 32-bit Windows, the
    32-bit compiler does require that the function be declared as __stdcall
    so that things will compile, link and run properly.
    
    https://bugzilla.gnome.org/show_bug.cgi?id-773299

 gdk/gdkvulkancontext.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gdk/gdkvulkancontext.c b/gdk/gdkvulkancontext.c
index e225f14..32478d8 100644
--- a/gdk/gdkvulkancontext.c
+++ b/gdk/gdkvulkancontext.c
@@ -670,7 +670,7 @@ gdk_display_create_vulkan_device (GdkDisplay  *display,
   return FALSE;
 }
 
-static VkBool32
+static VkBool32 VKAPI_CALL
 gdk_vulkan_debug_report (VkDebugReportFlagsEXT      flags,
                          VkDebugReportObjectTypeEXT objectType,
                          uint64_t                   object,