[PATCH] fast-export: don't segfault when marks file cannot be opened

[Sverre Rabbelier <srabbelier@gmail.com>]

The error function only prints an error message, resulting in a
segfault if we later on try to fprintf to a NULL handle.

Fix this by using die_errno instead.

Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
---

  This has been proken ever since this functionality was added in
  df6a7ff7 (add importing and exporting of revision marks) on
  Jun 11 2008 by Pieter de Bie (cc-ed). All other error calls
  seem to be appropriate.

  This should probably be applied to maint?

 builtin/fast-export.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index b0a4029..963e89b 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -503,7 +503,7 @@ static void export_marks(char *file)
 
 	f = fopen(file, "w");
 	if (!f)
-		error("Unable to open marks file %s for writing.", file);
+		die_errno("Unable to open marks file %s for writing", file);
 
 	for (i = 0; i < idnums.size; i++) {
 		if (deco->base && deco->base->type == 1) {
-- 
1.7.0.2.333.g70ce.dirty