Move ssl_check_timer() to public namespace

include/mbedtls/ssl_internal.h

diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index ca3f9cc..61c425c 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -1077,4 +1077,6 @@
 
 
 void mbedtls_ssl_set_timer( mbedtls_ssl_context *ssl, uint32_t millisecs );
+int mbedtls_ssl_check_timer( mbedtls_ssl_context *ssl );
+
 #endif /* ssl_internal.h */

library/ssl_tls.c

diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 13a8d47..37564d8 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -80,7 +80,7 @@
 /*
  * Return -1 is timer is expired, 0 if it isn't.
  */
-static int ssl_check_timer( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_check_timer( mbedtls_ssl_context *ssl )
 {
     if( ssl->f_get_timer == NULL )
         return( 0 );
@@ -3684,7 +3684,7 @@
          * This avoids by-passing the timer when repeatedly receiving messages
          * that will end up being dropped.
          */
-        if( ssl_check_timer( ssl ) != 0 )
+        if( mbedtls_ssl_check_timer( ssl ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 2, ( "timer has expired" ) );
             ret = MBEDTLS_ERR_SSL_TIMEOUT;
@@ -3763,7 +3763,7 @@
         {
             len = nb_want - ssl->in_left;
 
-            if( ssl_check_timer( ssl ) != 0 )
+            if( mbedtls_ssl_check_timer( ssl ) != 0 )
                 ret = MBEDTLS_ERR_SSL_TIMEOUT;
             else
             {