Merge 'sideband-bug' into HEAD

This works around the push-over-git-protocol issues pointed out in
https://github.com/msysgit/git/issues/101.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

Documentation/config.txt

@@ -3760,3 +3760,9 @@ worktree.guessRemote::
 	such a branch exists, it is checked out and set as "upstream"
 	for the new branch.  If no such match can be found, it falls
 	back to creating a new branch from the current HEAD.
+
+sendpack.sideband::
+  Allows to disable the side-band-64k capability for send-pack even
+  when it is advertised by the server. Makes it possible to work
+  around a limitation in the git for windows implementation together
+  with the dump git protocol. Defaults to true.

send-pack.c

@@ -38,6 +38,16 @@ int option_parse_push_signed(const struct option *opt,
 	die("bad %s argument: %s", opt->long_name, arg);
 }
 
+static int config_use_sideband = 1;
+
+static int send_pack_config(const char *var, const char *value, void *unused)
+{
+	if (!strcmp("sendpack.sideband", var))
+		config_use_sideband = git_config_bool(var, value);
+
+	return 0;
+}
+
 static void feed_object(const struct object_id *oid, FILE *fh, int negative)
 {
 	if (negative && !has_sha1_file(oid->hash))
@@ -392,6 +402,8 @@ int send_pack(struct send_pack_args *args,
 	struct async demux;
 	const char *push_cert_nonce = NULL;
 
+	git_config(send_pack_config, NULL);
+
 	/* Does the other end support the reporting? */
 	if (server_supports("report-status"))
 		status_report = 1;
@@ -399,7 +411,7 @@ int send_pack(struct send_pack_args *args,
 		allow_deleting_refs = 1;
 	if (server_supports("ofs-delta"))
 		args->use_ofs_delta = 1;
-	if (server_supports("side-band-64k"))
+	if (config_use_sideband && server_supports("side-band-64k"))
 		use_sideband = 1;
 	if (server_supports("quiet"))
 		quiet_supported = 1;