[gnome-builder] Fix meson targets introspection

[Christian Hergert <chergert src gnome org>]

commit 3e0166812b42c1d3eac633b1362b9a5c58c05b34
Author: Sergey Shatunov <me prok pw>
Date:   Fri Mar 23 11:35:52 2018 +0000

    Fix meson targets introspection

 src/plugins/meson/gbp-meson-build-target-provider.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/plugins/meson/gbp-meson-build-target-provider.c 
b/src/plugins/meson/gbp-meson-build-target-provider.c
index 2efadc895..6e5bfbd89 100644
--- a/src/plugins/meson/gbp-meson-build-target-provider.c
+++ b/src/plugins/meson/gbp-meson-build-target-provider.c
@@ -362,6 +362,7 @@ gbp_meson_build_target_provider_get_targets_async (IdeBuildTargetProvider *provi
   ide_subprocess_launcher_push_argv (launcher, "meson");
   ide_subprocess_launcher_push_argv (launcher, "introspect");
   ide_subprocess_launcher_push_argv (launcher, "--targets");
+  ide_subprocess_launcher_push_argv (launcher, ide_build_pipeline_get_builddir (pipeline));
 
   subprocess = ide_subprocess_launcher_spawn (launcher, cancellable, &error);