adjusted bigint code

configure

@@ -17522,6 +17522,18 @@ fi
 
 done
 
+for ac_header in dlfcn.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "dlfcn.h" "ac_cv_header_dlfcn_h" "$ac_includes_default"
+if test "x$ac_cv_header_dlfcn_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_DLFCN_H 1
+_ACEOF
+
+fi
+
+done
+