Fixes platform time_t abstraction

Fixes platform abstraction in error.c and the file that it's generated
from as well as DTLS samples.

include/mbedtls/platform.h

@@ -237,6 +237,8 @@ int mbedtls_platform_set_exit( void (*exit_func)( int status ) );
 #if defined(MBEDTLS_PLATFORM_TIME_TYPE_MACRO)
 typedef MBEDTLS_PLATFORM_TIME_TYPE_MACRO mbedtls_time_t;
 #else
+/* For time_t */
+#include <time.h>
 typedef time_t mbedtls_time_t;
 #endif /* MBEDTLS_PLATFORM_TIME_TYPE_MACRO */
 

library/error.c

@@ -34,6 +34,7 @@
 #include "mbedtls/platform.h"
 #else
 #define mbedtls_snprintf snprintf
+#define mbedtls_time_t   time_t
 #endif
 
 #if defined(MBEDTLS_ERROR_C)

programs/ssl/dtls_client.c

@@ -31,6 +31,7 @@
 #include <stdio.h>
 #define mbedtls_printf     printf
 #define mbedtls_fprintf    fprintf
+#define mbedtls_time_t     time_t
 #endif
 
 #if !defined(MBEDTLS_SSL_CLI_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) ||    \

programs/ssl/dtls_server.c

@@ -31,6 +31,7 @@
 #include <stdio.h>
 #define mbedtls_printf     printf
 #define mbedtls_fprintf    fprintf
+#define mbedtls_time_t     time_t
 #endif
 
 #if !defined(MBEDTLS_SSL_SRV_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) ||    \

scripts/data_files/error.fmt

@@ -34,6 +34,7 @@
 #include "mbedtls/platform.h"
 #else
 #define mbedtls_snprintf snprintf
+#define mbedtls_time_t   time_t
 #endif
 
 #if defined(MBEDTLS_ERROR_C)