Generate build time and date message at link time.

So it updates each time a bootloader changes, not just when bl*_main.c
files are recompiled.

Fixes ARM-software/tf-issues#33

Change-Id: Ie8e1a7bd7e1913d2e96ac268606284f76af8c5ab
Signed-off-by: Jon Medhurst <tixy@linaro.org>
diff --git a/bl31/bl31_main.c b/bl31/bl31_main.c
index 82449f5..536bb86 100644
--- a/bl31/bl31_main.c
+++ b/bl31/bl31_main.c
@@ -83,9 +83,8 @@
 	/* Perform platform setup in BL1 */
 	bl31_platform_setup();
 
-#if defined (__GNUC__)
-	printf("BL31 Built : %s, %s\n\r", __TIME__, __DATE__);
-#endif
+	printf("BL31 %s\n\r", build_message);
+
 	/* Initialise helper libraries */
 	bl31_lib_init();