Added explicit casts to prevent compiler warnings when trying to build for iOS
diff --git a/library/net.c b/library/net.c
index de1ec75..ec56800 100644
--- a/library/net.c
+++ b/library/net.c
@@ -497,7 +497,12 @@
 {
     struct timeval tv;
     tv.tv_sec  = 0;
+#if !defined(_WIN32) && (defined(__unix__) || defined(__unix) || \
+    (defined(__APPLE__) && defined(__MACH__)))
+    tv.tv_usec = (suseconds_t) usec;
+#else
     tv.tv_usec = usec;
+#endif
     select( 0, NULL, NULL, NULL, &tv );
 }
 #endif /* POLARSSL_HAVE_TIME */
@@ -508,7 +513,7 @@
 int net_recv( void *ctx, unsigned char *buf, size_t len )
 {
     int fd = *((int *) ctx);
-    int ret = read( fd, buf, len );
+    int ret = (int) read( fd, buf, len );
 
     if( ret < 0 )
     {
@@ -539,7 +544,7 @@
 int net_send( void *ctx, const unsigned char *buf, size_t len )
 {
     int fd = *((int *) ctx);
-    int ret = write( fd, buf, len );
+    int ret = (int) write( fd, buf, len );
 
     if( ret < 0 )
     {