Fixes SSL sample apps for non-default configs

Fixes the SSL sample applications to build for the non-default configs
which don't build if MBEDTLS_PLATFORM_C isn't defined.
diff --git a/programs/ssl/ssl_client1.c b/programs/ssl/ssl_client1.c
index 1aeddf7..3516e15 100644
--- a/programs/ssl/ssl_client1.c
+++ b/programs/ssl/ssl_client1.c
@@ -29,6 +29,9 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
+#define mbedtls_time       time 
+#define mbedtls_time_t     time_t
 #define mbedtls_fprintf    fprintf
 #define mbedtls_printf     printf
 #endif
diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 559e502..78f9e00 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -29,6 +29,9 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
+#define mbedtls_time       time
+#define mbedtls_time_t     time_t
 #define mbedtls_printf     printf
 #define mbedtls_fprintf    fprintf
 #define mbedtls_snprintf   snprintf
diff --git a/programs/ssl/ssl_mail_client.c b/programs/ssl/ssl_mail_client.c
index 974c170..c807eb5 100644
--- a/programs/ssl/ssl_mail_client.c
+++ b/programs/ssl/ssl_mail_client.c
@@ -29,6 +29,9 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
+#define mbedtls_time       time
+#define mbedtls_time_t     time_t 
 #define mbedtls_fprintf    fprintf
 #define mbedtls_printf     printf
 #endif
diff --git a/programs/ssl/ssl_server.c b/programs/ssl/ssl_server.c
index 70efba9..c7f5267 100644
--- a/programs/ssl/ssl_server.c
+++ b/programs/ssl/ssl_server.c
@@ -29,6 +29,9 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
+#define mbedtls_time       time
+#define mbedtls_time_t     time_t 
 #define mbedtls_fprintf    fprintf
 #define mbedtls_printf     printf
 #endif
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index b586a70..6d4e916 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -29,7 +29,10 @@
 #include "mbedtls/platform.h"
 #else
 #include <stdio.h>
+#include <stdlib.h>
 #define mbedtls_free       free
+#define mbedtls_time       time
+#define mbedtls_time_t     time_t
 #define mbedtls_calloc    calloc
 #define mbedtls_fprintf    fprintf
 #define mbedtls_printf     printf
diff --git a/programs/test/udp_proxy.c b/programs/test/udp_proxy.c
index eb8d29e..b698c78 100644
--- a/programs/test/udp_proxy.c
+++ b/programs/test/udp_proxy.c
@@ -34,11 +34,15 @@
 #if defined(MBEDTLS_PLATFORM_C)
 #include "mbedtls/platform.h"
 #else
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#define mbedtls_time       time
+#define mbedtls_time_t     time_t
 #define mbedtls_printf     printf
 #endif
 
 #if !defined(MBEDTLS_NET_C)
-#include <stdio.h>
 int main( void )
 {
     mbedtls_printf( "MBEDTLS_NET_C not defined.\n" );
@@ -50,10 +54,7 @@
 #include "mbedtls/error.h"
 #include "mbedtls/ssl.h"
 
-#include <stdio.h>
-#include <stdlib.h>
 #include <string.h>
-#include <time.h>
 
 /* For select() */
 #if (defined(_WIN32) || defined(_WIN32_WCE)) && !defined(EFIX64) && \