Add missing includes.

Caused warnings about implicitly defined malloc() and sprintf().

Change-Id: Ia56309adc11caf5801ffd88e374c512b785cfd93
diff --git a/libcutils/tzstrftime.c b/libcutils/tzstrftime.c
index e37d79a..e4f54df 100644
--- a/libcutils/tzstrftime.c
+++ b/libcutils/tzstrftime.c
@@ -8,6 +8,7 @@
 #endif /* !defined NOID */
 #endif /* !defined lint */
 
+#include <stdio.h>
 #include <time.h>
 #include <tzfile.h>
 #include <limits.h>