[glib/vs2012-2-68: 1/3] option-context.c: Define NAN if not defined

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

commit a634e1077dc19695f95346b0b0ef2c8af4e5c896
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Mar 31 16:52:18 2021 +0800

    option-context.c: Define NAN if not defined
    
    This will enable the build to succeed on compilers that don't support
    NAN yet.

 glib/tests/option-context.c | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/glib/tests/option-context.c b/glib/tests/option-context.c
index 1c588d742..e68bbe74e 100644
--- a/glib/tests/option-context.c
+++ b/glib/tests/option-context.c
@@ -28,6 +28,9 @@
 #include <locale.h>
 #include <math.h>
 
+#ifndef NAN
+#define NAN HUGE_VAL * 0.0f
+#endif
 
 static GOptionEntry main_entries[] = {
   { "main-switch", 0, 0,