[gnome-builder] rustup: enforce xterm-256color for $TERM with PTY

[Christian Hergert <chergert src gnome org>]

commit 73abe9343eb03435e1c1737fc43c5a7f97da7d65
Author: Christian Hergert <chergert redhat com>
Date:   Sun Mar 19 17:24:38 2017 -0700

    rustup: enforce xterm-256color for $TERM with PTY
    
    We need to ensure that the inferior things that we are a terminal. It seems
    to also rely on $TERM in addition to isatty().

 plugins/rustup/rustup_plugin/__init__.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/plugins/rustup/rustup_plugin/__init__.py b/plugins/rustup/rustup_plugin/__init__.py
index c542e27..c2580c6 100644
--- a/plugins/rustup/rustup_plugin/__init__.py
+++ b/plugins/rustup/rustup_plugin/__init__.py
@@ -330,6 +330,8 @@ class RustupInstaller(Ide.Transfer):
         launcher.take_stdout_fd(os.dup(slave_fd))
         launcher.take_stderr_fd(os.dup(slave_fd))
 
+        launcher.setenv('TERM', 'xterm-256color', True)
+
         data_stream = Gio.DataInputStream.new(Gio.UnixInputStream.new(os.dup(master_fd), True))
         # set it to ANY so the progress bars can be parsed
         data_stream.set_newline_type(Gio.DataStreamNewlineType.ANY)