Teach --text option to diff

Add new item text to struct diff_options.
If set then do not try to detect binary files.
Signed-off-by: NStephan Feder <sf@b-i-t.de>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

diff.c

@@ -723,7 +723,7 @@ static void builtin_diff(const char *name_a,
 	if (fill_mmfile(&mf1, one) < 0 || fill_mmfile(&mf2, two) < 0)
 		die("unable to read files to diff");
 
-	if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
+	if (!o->text && (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2))) {
 		/* Quite common confusing case */
 		if (mf1.size == mf2.size &&
 		    !memcmp(mf1.ptr, mf2.ptr, mf1.size))
@@ -1561,6 +1561,9 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		options->output_format |= DIFF_FORMAT_PATCH;
 		options->full_index = options->binary = 1;
 	}
+	else if (!strcmp(arg, "--text")) {
+		options->text = 1;
+	}
 	else if (!strcmp(arg, "--name-only"))
 		options->output_format |= DIFF_FORMAT_NAME;
 	else if (!strcmp(arg, "--name-status"))

diff.h

@@ -42,6 +42,7 @@ struct diff_options {
 	unsigned recursive:1,
 		 tree_in_recursive:1,
 		 binary:1,
+		 text:1,
 		 full_index:1,
 		 silent_on_remove:1,
 		 find_copies_harder:1,