Bug 1571316 - Fix undefined PORT_Assert reference in ARMv7 make build…

…s r=jcj

The recent x25519 update added some assertions in `curve25519_32.c`. For these, we need to include a new header file in order to support Makefile builds on armv7.

Differential Revision: https://phabricator.services.mozilla.com/D40752

--HG--
extra : moz-landing-system : lando

lib/freebl/ecl/curve25519_32.c

@@ -29,6 +29,10 @@
  *  1. Convert custom integer types to stdint.h types
  */
 
+#ifdef FREEBL_NO_DEPEND
+#include "../stubs.h"
+#endif
+
 #include "ecl-priv.h"
 
 /* fe means field element. Here the field is \Z/(2^255-19). An element t,