[template-glib] expr-eval: fix translation to double for math func

[Christian Hergert <chergert src gnome org>]

commit 1fbd74c23b99ef9c96b3d79a843d14af239620da
Author: Christian Hergert <chergert redhat com>
Date:   Fri May 6 15:20:15 2022 -0700

    expr-eval: fix translation to double for math func

 src/tmpl-expr-eval.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/tmpl-expr-eval.c b/src/tmpl-expr-eval.c
index d6280b6..7287001 100644
--- a/src/tmpl-expr-eval.c
+++ b/src/tmpl-expr-eval.c
@@ -2086,6 +2086,7 @@ builtin_##func (const GValue  *value,                                   \
                                                                         \
   if (!G_VALUE_HOLDS_DOUBLE (value))                                    \
     {                                                                   \
+      g_value_init (&translated, G_TYPE_DOUBLE);                        \
       if (!g_value_transform (value, &translated))                      \
         {                                                               \
           g_set_error (error,                                           \