[gssdp] build: Add gir build dir

[Jens Georg <jensgeorg src gnome org>]

commit 89b3ac92a0b82615d0f7d4f3629a7b05f6bc584e
Author: Jens Georg <mail jensge org>
Date:   Sat May 22 19:53:28 2021 +0200

    build: Add gir build dir
    
    For use in vapi generation in subproject

 libgssdp/meson.build | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/libgssdp/meson.build b/libgssdp/meson.build
index f3d20da..7fd8b4c 100644
--- a/libgssdp/meson.build
+++ b/libgssdp/meson.build
@@ -81,6 +81,7 @@ pkg.generate(libgssdp,
              requires_private: ['gobject-2.0', 'gio-2.0'])
 
 if get_option('introspection')
+    gssdp_gir_dir = meson.current_build_dir()
     gir = gnome.generate_gir(libgssdp,
             sources : headers + sources + enums,
             namespace : 'GSSDP',