[gtk/fix.builder.msvc] testsuite/gtk/builder.c: Fix running on Visual Studio

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

commit 1e4d3b6ca157d74f69b7200946083c6cda6c827f
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Thu Oct 8 16:05:40 2020 +0800

    testsuite/gtk/builder.c: Fix running on Visual Studio
    
    Explicitly say in the code that we are exporting the symbols so that when the
    test program runs, it can find the required builder symbols.

 testsuite/gtk/builder.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/testsuite/gtk/builder.c b/testsuite/gtk/builder.c
index 78ff3c9b3a..d57b676d56 100644
--- a/testsuite/gtk/builder.c
+++ b/testsuite/gtk/builder.c
@@ -2448,13 +2448,13 @@ test_transforms (void)
   g_object_unref (builder);
 }
 
-char *
+G_MODULE_EXPORT char *
 builder_get_search (gpointer item)
 {
   return g_strdup (gtk_string_filter_get_search (item));
 }
 
-char *
+G_MODULE_EXPORT char *
 builder_copy_arg (gpointer item, const char *arg)
 {
   return g_strdup (arg);