Guard tinycrypt files with MBEDTLS_USE_UECC
diff --git a/include/tinycrypt/ecc_dh.h b/include/tinycrypt/ecc_dh.h
index b828e19..18a4fd2 100644
--- a/include/tinycrypt/ecc_dh.h
+++ b/include/tinycrypt/ecc_dh.h
@@ -66,6 +66,7 @@
  *  Security: The curve NIST p-256 provides approximately 128 bits of security.
  */
 
+#if defined(MBEDTLS_USE_UECC)
 #ifndef __TC_ECC_DH_H__
 #define __TC_ECC_DH_H__
 
@@ -129,3 +130,4 @@
 #endif
 
 #endif /* __TC_ECC_DH_H__ */
+#endif /* MBEDTLS_USE_UECC */