[vte/vte-0-48] pty: spawn: Always fill in the GError on failure

[Christian Persch <chpe src gnome org>]

commit 1e6071305c34cb3b5ea0548c7b01710492acd55e
Author: Christian Persch <chpe src gnome org>
Date:   Tue Apr 25 23:06:13 2017 +0200

    pty: spawn: Always fill in the GError on failure
    
    (cherry picked from commit d2e38f44ec644f94e79f6aa923da5b57601a47df)

 src/pty.cc |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)
---
diff --git a/src/pty.cc b/src/pty.cc
index 5006cc7..646a4e0 100644
--- a/src/pty.cc
+++ b/src/pty.cc
@@ -364,8 +364,15 @@ __vte_pty_spawn (VtePty *pty,
         GError *err = NULL;
         GPollFD pollfd;
 
-        if (cancellable && !g_cancellable_make_pollfd(cancellable, &pollfd))
+        if (cancellable && !g_cancellable_make_pollfd(cancellable, &pollfd)) {
+                vte::util::restore_errno errsv;
+                g_set_error(error,
+                            G_IO_ERROR,
+                            g_io_error_from_errno(errsv),
+                            "Failed to make cancellable pollfd: %s",
+                            g_strerror(errsv));
                 return FALSE;
+        }
 
         spawn_flags |= G_SPAWN_DO_NOT_REAP_CHILD;