Fix single threaded builds
diff --git a/include/mbedtls/threading.h b/include/mbedtls/threading.h
index c39cbf2..b416d47 100644
--- a/include/mbedtls/threading.h
+++ b/include/mbedtls/threading.h
@@ -81,6 +81,7 @@
void mbedtls_threading_free_alt( void );
#endif /* MBEDTLS_THREADING_ALT */
+#if defined(MBEDTLS_THREADING_C)
/*
* The function pointers for mutex_init, mutex_free, mutex_ and mutex_unlock
*
@@ -96,6 +97,7 @@
*/
extern mbedtls_threading_mutex_t mbedtls_threading_readdir_mutex;
extern mbedtls_threading_mutex_t mbedtls_threading_gmtime_mutex;
+#endif
#ifdef __cplusplus
}