Fix compiler error.

Change-Id: Iaa0ecd02e8c25ec1ebdd67a09e8b4ca961375318

kal/posix/include/signal.h

@@ -10,6 +10,7 @@ extern "C" {
 #endif
 
 #define __NEED_pthread_attr_t
+#define __NEED_time_t
 
 #include <bits/alltypes.h>
 

kal/posix/include/time.h

@@ -3,6 +3,10 @@
 
 #ifdef __ICCARM__ /* for iar */
 
+#if !defined(_DLIB_TIME_USES_64) || !defined(_DLIB_TIME_USES_LONG) || (_DLIB_TIME_USES_64 == 0) || (_DLIB_TIME_USES_LONG == 0)
+#error "_DLIB_TIME_USES_64=1 and _DLIB_TIME_USES_LONG=1 should be defined in IAR project(C/C++ Compiler->Preprocessor->Defined symbols)."
+#endif
+
 #ifndef tm_isdst
 #define tm_isdst    tm_isdst;	\
 	long __tm_gmtoff;	\