diff --git a/src/config.h.in b/src/config.h.in
index 50d29f5513..c1589b5d5a 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -43,3 +43,9 @@
 
 /* Define to 1 if you can safely include both <sys/time.h> and <time.h>. */
 #undef TIME_WITH_SYS_TIME
+
+/* Number of bits in a file offset, on hosts where this is settable. */
+#undef _FILE_OFFSET_BITS
+
+/* Define for large files, on AIX-style hosts. */
+#undef _LARGE_FILES