[vala/wip/muktupavels/vala-extern] codegen: append VALA_EXTERN also when using fast-vapi

[Alberts Muktupāvels <muktupavels src gnome org>]

commit c6b0ffab3165522d2764154b0562117d932d0cec
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Mon Oct 10 14:25:22 2022 +0300

    codegen: append VALA_EXTERN also when using fast-vapi

 codegen/valaccodebasemodule.vala | 8 ++++++++
 1 file changed, 8 insertions(+)
---
diff --git a/codegen/valaccodebasemodule.vala b/codegen/valaccodebasemodule.vala
index fb323e28e..b9bdbcbf8 100644
--- a/codegen/valaccodebasemodule.vala
+++ b/codegen/valaccodebasemodule.vala
@@ -866,6 +866,14 @@ public abstract class Vala.CCodeBaseModule : CodeGenerator {
                 * C code output.
                 */
                if (source_file.file_type == SourceFileType.FAST) {
+                       if (requires_vala_extern) {
+                               if (context.header_filename != null) {
+                                       if (!header_file.add_declaration ("VALA_EXTERN")) {
+                                               append_vala_extern_define (header_file);
+                                       }
+                                       internal_header_file.add_include (source_file.get_cinclude_filename 
(), true);
+                               }
+                       }
                        return;
                }