make it possible to access Regs and Tag codes from external sources.

include/YapRegs.h

@@ -0,0 +1,28 @@
+#ifndef YAP_REGS_H
+
+#define YAP_REGS_H 1
+
+#if defined(TABLING) || defined(YAPOR_SBA)
+typedef struct trail_frame {
+  Term term;
+  CELL value;
+} *tr_fr_ptr;
+
+#define TrailTerm(X)   ((X)->term)
+#else
+typedef Term *tr_fr_ptr;
+
+#define TrailTerm(X)   ((X)->term)
+#endif
+
+typedef void *choiceptr;
+
+typedef void *yamop;
+
+typedef char *ADDR;
+
+#define RESET_VARIABLE(X) (*(X) = (CELL)(X))
+
+#include "src/Regs.h"
+
+#endif