patchgit-add -u: match the index with working tree.

diff --git a/builtin-add.c b/builtin-add.c
index 9ec2925..5e6748f 100644
--- a/builtin-add.c
+++ b/builtin-add.c
@@ -8,10 +8,15 @@
 #include "dir.h"
 #include "exec_cmd.h"
 #include "cache-tree.h"
+#include "diff.h"
+#include "diffcore.h"
+#include "commit.h"
+#include "revision.h"
 
 static const char builtin_add_usage[] =
-"git-add [-n] [-v] [-f] [--interactive | -i] [--] <filepattern>...";
+"git-add [-n] [-v] [-f] [--interactive | -i] [-u] [--] <filepattern>...";
 
+static int take_all_worktree_changes;
 static const char *excludes_file;
 
 static void prune_directory(struct dir_struct *dir, const char **pathspec, int prefix)
@@ -92,6 +97,44 @@ static void fill_directory(struct dir_struct *dir, const char **pathspec)
 		prune_directory(dir, pathspec, baselen);
 }
 
+static void update_callback(struct diff_queue_struct *q,
+			    struct diff_options *opt, void *cbdata)
+{
+	int i, verbose;
+
+	verbose = *((int *)cbdata);
+	for (i = 0; i < q->nr; i++) {
+		struct diff_filepair *p = q->queue[i];
+		const char *path = p->one->path;
+		switch (p->status) {
+		default:
+			die("unexpacted diff status %c", p->status);
+		case DIFF_STATUS_UNMERGED:
+		case DIFF_STATUS_MODIFIED:
+			add_file_to_cache(path, verbose);
+			break;
+		case DIFF_STATUS_DELETED:
+			remove_file_from_cache(path);
+			if (verbose)
+				printf("remove '%s'\n", path);
+			break;
+		}
+	}
+}
+
+static void update_all(int verbose)
+{
+	struct rev_info rev;
+	init_revisions(&rev, "");
+	setup_revisions(0, NULL, &rev, NULL);
+	rev.diffopt.output_format = DIFF_FORMAT_CALLBACK;
+	rev.diffopt.format_callback = update_callback;
+	rev.diffopt.format_callback_data = &verbose;
+	if (read_cache() < 0)
+		die("index file corrupt");
+	run_diff_files(&rev, 0);
+}
+
 static int git_add_config(const char *var, const char *value)
 {
 	if (!strcmp(var, "core.excludesfile")) {
@@ -156,8 +199,20 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 			verbose = 1;
 			continue;
 		}
+		if (!strcmp(arg, "-u")) {
+			take_all_worktree_changes = 1;
+			continue;
+		}
 		usage(builtin_add_usage);
 	}
+
+	if (take_all_worktree_changes) {
+		if (i < argc)
+			die("-u and explicit paths are incompatible");
+		update_all(verbose);
+		goto finish;
+	}
+
 	if (argc <= i) {
 		fprintf(stderr, "Nothing specified, nothing added.\n");
 		fprintf(stderr, "Maybe you wanted to say 'git add .'?\n");
@@ -207,6 +262,7 @@ int cmd_add(int argc, const char **argv, const char *prefix)
 	for (i = 0; i < dir.nr; i++)
 		add_file_to_cache(dir.entries[i]->name, verbose);
 
+ finish:
 	if (active_cache_changed) {
 		if (write_cache(newfd, active_cache, active_nr) ||
 		    close(newfd) || commit_locked_index(&lock_file))

diff --git a/unpack-trees.c b/unpack-trees.c
index 5139481..1419653 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -288,73 +288,15 @@ static void unlink_entry(char *name)
 	}
 }
 
-static volatile sig_atomic_t progress_update;
-
-static void progress_interval(int signum)
-{
-	progress_update = 1;
-}
-
-static void setup_progress_signal(void)
-{
-	struct sigaction sa;
-	struct itimerval v;
-
-	memset(&sa, 0, sizeof(sa));
-	sa.sa_handler = progress_interval;
-	sigemptyset(&sa.sa_mask);
-	sa.sa_flags = SA_RESTART;
-	sigaction(SIGALRM, &sa, NULL);
-
-	v.it_interval.tv_sec = 1;
-	v.it_interval.tv_usec = 0;
-	v.it_value = v.it_interval;
-	setitimer(ITIMER_REAL, &v, NULL);
-}
-
 static struct checkout state;
 static void check_updates(struct cache_entry **src, int nr,
 		struct unpack_trees_options *o)
 {
 	unsigned short mask = htons(CE_UPDATE);
-	unsigned last_percent = 200, cnt = 0, total = 0;
-
-	if (o->update && o->verbose_update) {
-		for (total = cnt = 0; cnt < nr; cnt++) {
-			struct cache_entry *ce = src[cnt];
-			if (!ce->ce_mode || ce->ce_flags & mask)
-				total++;
-		}
-
-		/* Don't bother doing this for very small updates */
-		if (total < 250)
-			total = 0;
-
-		if (total) {
-			fprintf(stderr, "Checking files out...\n");
-			setup_progress_signal();
-			progress_update = 1;
-		}
-		cnt = 0;
-	}
 
 	while (nr--) {
 		struct cache_entry *ce = *src++;
 
-		if (total) {
-			if (!ce->ce_mode || ce->ce_flags & mask) {
-				unsigned percent;
-				cnt++;
-				percent = (cnt * 100) / total;
-				if (percent != last_percent ||
-				    progress_update) {
-					fprintf(stderr, "%4u%% (%u/%u) done\r",
-						percent, cnt, total);
-					last_percent = percent;
-					progress_update = 0;
-				}
-			}
-		}
 		if (!ce->ce_mode) {
 			if (o->update)
 				unlink_entry(ce->name);
@@ -366,10 +308,6 @@ static void check_updates(struct cache_entry **src, int nr,
 				checkout_entry(ce, &state, NULL);
 		}
 	}
-	if (total) {
-		signal(SIGALRM, SIG_IGN);
-		fputc('\n', stderr);
-	}
 }
 
 int unpack_trees(struct object_list *trees, struct unpack_trees_options *o)