Make git-diff-tree --pretty

@@ -323,7 +323,8 @@ static char *generate_header(const char 
 	offset = sprintf(this_header, "%s%s (from %s)\n", header_prefix, commit, parent);
 	if (verbose_header) {
 		offset += pretty_print_commit(commit_format, msg, len, this_header + offset, sizeof(this_header) - offset);
-		this_header[offset++] = '\n';
+		if (diff_output_format != DIFF_FORMAT_NO_OUTPUT)
+			this_header[offset++] = '\n';
 		this_header[offset++] = 0;
 	}
 

@@ -400,6 +401,19 @@ static int diff_tree_stdin(char *line)
 static char *diff_tree_usage =
 "git-diff-tree [-p] [-r] [-z] [--stdin] [-M] [-C] [-R] [-S<string>] [-O<orderfile>] [-m] [-s] [-v] [-t] <tree-ish> <tree-ish>";
 
+static enum cmit_fmt get_commit_format(const char *arg)
+{
+	if (!*arg)
+		return CMIT_FMT_DEFAULT;
+	if (!strcmp(arg, "=raw"))
+		return CMIT_FMT_RAW;
+	if (!strcmp(arg, "=medium"))
+		return CMIT_FMT_MEDIUM;
+	if (!strcmp(arg, "=short"))
+		return CMIT_FMT_SHORT;
+	usage(diff_tree_usage);	
+}			
+
 int main(int argc, const char **argv)
 {
 	int nr_sha1;

@@ -492,6 +506,12 @@ int main(int argc, const char **argv)
 			header_prefix = "diff-tree ";
 			continue;
 		}
+		if (!strncmp(arg, "--pretty", 8)) {
+			commit_format = get_commit_format(arg+8);
+			verbose_header = 1;
+			header_prefix = "diff-tree ";
+			continue;
+		}
 		if (!strcmp(arg, "--stdin")) {
 			read_stdin = 1;
 			continue;