[gnome-builder/wip/chergert/bug1] debugger: make prepare optional

[Christian Hergert <chergert src gnome org>]

commit 814cf4803ce433ea07dfbb8fa3b2219066c99b43
Author: Christian Hergert <chergert redhat com>
Date:   Sat Aug 26 19:43:29 2017 -0700

    debugger: make prepare optional

 libide/debugger/ide-debugger.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/libide/debugger/ide-debugger.c b/libide/debugger/ide-debugger.c
index 05b3eb3..2681c9e 100644
--- a/libide/debugger/ide-debugger.c
+++ b/libide/debugger/ide-debugger.c
@@ -1992,5 +1992,6 @@ ide_debugger_prepare (IdeDebugger *self,
   g_return_if_fail (IDE_IS_DEBUGGER (self));
   g_return_if_fail (IDE_IS_RUNNER (runner));
 
-  IDE_DEBUGGER_GET_CLASS (self)->prepare (self, runner);
+  if (IDE_DEBUGGER_GET_CLASS (self)->prepare)
+    IDE_DEBUGGER_GET_CLASS (self)->prepare (self, runner);
 }