Upgrade to upstream tip of tree strace.

Change-Id: I56ccbfbb64885c61f160145f181e42dab78adefb
diff --git a/vsprintf.c b/vsprintf.c
index f6019f0..0125e72 100644
--- a/vsprintf.c
+++ b/vsprintf.c
@@ -11,11 +11,15 @@
 
 #include "defs.h"
 
-#ifdef USE_CUSTOM_PRINTF
+#if USE_CUSTOM_PRINTF
 
 #include <stdarg.h>
 #include <limits.h>
 
+#ifndef HAVE_FPUTS_UNLOCKED
+# define fputs_unlocked fputs
+#endif
+
 #define noinline_for_stack /*nothing*/
 #define likely(expr)       (expr)
 #define unlikely(expr)     (expr)