[gnome-builder] meson: add some user warnings about missing meson/ninja

[Christian Hergert <chergert src gnome org>]

commit 92729f7ea833a4bd9c81852d149d3e0c229e4b2e
Author: Christian Hergert <chergert redhat com>
Date:   Tue May 1 14:58:30 2018 -0700

    meson: add some user warnings about missing meson/ninja
    
    Fixes #488

 src/plugins/meson/gbp-meson-pipeline-addin.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)
---
diff --git a/src/plugins/meson/gbp-meson-pipeline-addin.c b/src/plugins/meson/gbp-meson-pipeline-addin.c
index 965ec7f9e..a4fb4ca11 100644
--- a/src/plugins/meson/gbp-meson-pipeline-addin.c
+++ b/src/plugins/meson/gbp-meson-pipeline-addin.c
@@ -99,7 +99,8 @@ gbp_meson_pipeline_addin_load (IdeBuildPipelineAddin *addin,
 
   if (ninja == NULL)
     {
-      g_debug ("Failed to locate ninja. Meson building is disabled.");
+      ide_context_warning (context,
+                           _("A Meson-based project is loaded but Ninja could not be found."));
       IDE_EXIT;
     }
 
@@ -117,6 +118,10 @@ gbp_meson_pipeline_addin_load (IdeBuildPipelineAddin *addin,
   if (NULL == (meson = ide_configuration_getenv (config, "MESON")))
     meson = "meson";
 
+  if (!ide_runtime_contains_program_in_path (runtime, meson, NULL))
+    ide_context_warning (context,
+                         _("A Meson-based project is loaded but meson could not be found."));
+
   /* Setup our meson configure stage. */
 
   ide_subprocess_launcher_push_argv (config_launcher, meson);