[PATCH 6/6] diff: run external diff helper with shell

[Jeff King <peff@peff.net>]

This is mostly to make it more consistent with the rest of
git, which uses the shell to exec helpers.

Signed-off-by: Jeff King <peff@peff.net>
---
Consistency is the main advantage here. Though I think you can actually
do craziness like setting

  GIT_EXTERNAL_DIFF='my-command $2 $3 && true' git diff

to pick out some subset of the parameters, I can't imagine it is
actually a good idea.

 diff.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/diff.c b/diff.c
index 2794238..9bb40bc 100644
--- a/diff.c
+++ b/diff.c
@@ -2294,7 +2294,7 @@ static void run_external_diff(const char *pgm,
 	}
 	*arg = NULL;
 	fflush(NULL);
-	retval = run_command_v_opt(spawn_arg, 0);
+	retval = run_command_v_opt(spawn_arg, RUN_USING_SHELL);
 	remove_tempfile();
 	if (retval) {
 		fprintf(stderr, "external diff died, stopping at %s.\n", name);
-- 
1.6.6.65.g050d2.dirty