[gnome-builder] diagnostics-manager: add a check for thread safety

[Matthew Leeds <mwleeds src gnome org>]

commit 4ede93622cce378ffef99cf9c9603f2ec13d0fdb
Author: Matthew Leeds <mleeds redhat com>
Date:   Wed Feb 22 15:32:35 2017 -0600

    diagnostics-manager: add a check for thread safety
    
    Adding this check makes sure multiple threads don't try to do the same
    diagnostics work at the same time, and prevents an assertion failure in
    ide_diagnostics_group_diagnose().
    
    https://bugzilla.gnome.org/show_bug.cgi?id=779076

 libide/diagnostics/ide-diagnostics-manager.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libide/diagnostics/ide-diagnostics-manager.c b/libide/diagnostics/ide-diagnostics-manager.c
index 0b94963..3ba0233 100644
--- a/libide/diagnostics/ide-diagnostics-manager.c
+++ b/libide/diagnostics/ide-diagnostics-manager.c
@@ -500,7 +500,7 @@ ide_diagnostics_manager_begin_diagnose (gpointer data)
     {
       IdeDiagnosticsGroup *group = value;
 
-      if (group->needs_diagnose && group->adapter != NULL)
+      if (group->needs_diagnose && group->adapter != NULL && group->in_diagnose == 0)
         ide_diagnostics_group_diagnose (group, self);
     }