Gcc and clang can check format strings of printf-like functions

Since we don't support any other compilers right now, enable that
extension unconditionally.

Fix the bugs found by format string checking.

Corresponding to flashrom svn r1032.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
Acked-by: Sean Nelson <audiohacked@gmail.com>
diff --git a/udelay.c b/udelay.c
index b395971..8bfba63 100644
--- a/udelay.c
+++ b/udelay.c
@@ -91,7 +91,7 @@
 	msg_pinfo("Calibrating delay loop... ");
 	resolution = measure_os_delay_resolution();
 	if (resolution) {
-		msg_pdbg("OS timer resolution is %u usecs, ", resolution);
+		msg_pdbg("OS timer resolution is %lu usecs, ", resolution);
 	} else {
 		msg_pinfo("OS timer resolution is unusable. ");
 	}