assert.h only for internal files
diff --git a/skeletons/asn_internal.h b/skeletons/asn_internal.h
index c2aa9e5..22011ef 100644
--- a/skeletons/asn_internal.h
+++ b/skeletons/asn_internal.h
@@ -13,6 +13,10 @@
#include <asn_application.h> /* Application-visible API */
+#ifndef __NO_ASSERT_H__ /* Include assert.h only for internal use. */
+#include <assert.h> /* for assert() macro */
+#endif
+
#define CALLOC(nmemb, size) calloc(nmemb, size)
#define MALLOC(size) malloc(size)
#define REALLOC(oldptr, size) realloc(oldptr, size)