futility: add version command

BUG=none
BRANCH=none
TEST=manual

make && ./build/futility/futility version

Change-Id: I362b13d3befba62a33bc9fd2e87ad68f4bc62a84
Signed-off-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/226779
Reviewed-by: Randall Spangler <rspangler@chromium.org>
diff --git a/futility/futility.c b/futility/futility.c
index b407061..c74bba6 100644
--- a/futility/futility.c
+++ b/futility/futility.c
@@ -237,6 +237,16 @@
 		      "Show a bit of help (you're looking at it)",
 		      print_help);
 
+static int do_version(int argc, char *argv[])
+{
+	printf("%s\n", futility_version);
+	return 0;
+}
+
+DECLARE_FUTIL_COMMAND(version, do_version,
+		      "Show the futility source revision and build date",
+		      NULL);
+
 /*
  * These are built-in functions that we'd like to abandon completely someday.
  * TODO: If no one complains, get rid of them.