[dasher] Fix crash in direct mode if copy/speak-all-on-stop enabled

[Patrick Welche <pwelche src gnome org>]

commit c416cfa439b2c267f7d1f14b7c6ba478e958276d
Author: Alan Lawrence <acl33 inf phy cam ac uk>
Date:   Sat Jan 1 20:26:04 2011 +0000

    Fix crash in direct mode if copy/speak-all-on-stop enabled
    
    (Still fails to copy all / speak all, but that's probably for the best?!)

 Src/Gtk2/dasher_editor_external.cpp |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/Src/Gtk2/dasher_editor_external.cpp b/Src/Gtk2/dasher_editor_external.cpp
index 6c4e82b..51088db 100644
--- a/Src/Gtk2/dasher_editor_external.cpp
+++ b/Src/Gtk2/dasher_editor_external.cpp
@@ -228,7 +228,7 @@ dasher_editor_external_command(DasherEditor *pSelf, const gchar *szCommand) {
 // TODO: We shouldn't need to know about the buffer here - make this a method of the buffer set
 static const gchar *
 dasher_editor_external_get_all_text(DasherEditor *pSelf) { 
-  return NULL;
+  return "";
 }
 
 static const gchar *