[PATCH] ls-files: die instead of fprintf/exit in -i error

[Ben Walton <bwalton@artsci.utoronto.ca>]

When ls-files was called with -i but no exclude pattern, it was
calling fprintf(stderr, "...", NULL) and then exiting.  On Solaris,
passing NULL into fprintf was causing a segfault.  On glibc systems,
it was simply producing incorrect output (eg: "(null)": ...).  The
NULL pointer was a result of argv[0] not being preserved by the option
parser.  Instead of requesting that the option parser preserve
argv[0], use die() with a constant string.

A trigger for this bug was: `git ls-files -i`

Signed-off-by: Ben Walton <bwalton@artsci.utoronto.ca>
---
This is the alternate solution to this bug as proposed earlier today.
I don't have a preference either way for which solution is better or
more inline with the 'git way,' so please choose the most appropriate.

I've run the test suite with both patches on Linux and Solaris
and everything passes.

 builtin-ls-files.c |    7 ++-----
 1 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/builtin-ls-files.c b/builtin-ls-files.c
index f473220..2c95ca6 100644
--- a/builtin-ls-files.c
+++ b/builtin-ls-files.c
@@ -524,11 +524,8 @@ int cmd_ls_files(int argc, const char **argv, const char *prefix)
 		ps_matched = xcalloc(1, num);
 	}
 
-	if ((dir.flags & DIR_SHOW_IGNORED) && !exc_given) {
-		fprintf(stderr, "%s: --ignored needs some exclude pattern\n",
-			argv[0]);
-		exit(1);
-	}
+	if ((dir.flags & DIR_SHOW_IGNORED) && !exc_given)
+		die("ls-files --ignored needs some exclude pattern");
 
 	/* With no flags, we default to showing the cached files */
 	if (!(show_stage | show_deleted | show_others | show_unmerged |
-- 
1.6.4.4