[vte] widget: Set error from vte_terminal_set_encoding when built without ICU

[Christian Persch <chpe src gnome org>]

commit 9a21d415720a9c1981c29429e32a6521de056a99
Author: Christian Persch <chpe src gnome org>
Date:   Thu Apr 23 00:06:04 2020 +0200

    widget: Set error from vte_terminal_set_encoding when built without ICU

 src/vte.cc | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/src/vte.cc b/src/vte.cc
index 3d39bfc7..95854516 100644
--- a/src/vte.cc
+++ b/src/vte.cc
@@ -2061,6 +2061,8 @@ Terminal::set_encoding(char const* charset,
 
         return true;
 #else
+        g_set_error_literal(error, G_CONVERT_ERROR, G_CONVERT_ERROR_NO_CONVERSION,
+                            "ICU support not available");
         return false;
 #endif
 }