diff --git a/libguile/scmconfig.h.in b/libguile/scmconfig.h.in
index fe841648f..278534839 100644
--- a/libguile/scmconfig.h.in
+++ b/libguile/scmconfig.h.in
@@ -170,6 +170,12 @@
 /* This is included as part of a workaround for a autoheader bug. */
 #undef HAVE_REGCOMP
 
+/* Define if the operating system supplies bzero without declaring it. */
+#undef DECLARE_BZERO
+
+/* Define if the operating system supplies usleep without declaring it. */
+#undef DECLARE_USLEEP
+
 /* Define if you have the bzero function.  */
 #undef HAVE_BZERO
 
@@ -326,6 +332,9 @@
 /* Define if you have the uname function.  */
 #undef HAVE_UNAME
 
+/* Define if you have the usleep function.  */
+#undef HAVE_USLEEP
+
 /* Define if you have the waitpid function.  */
 #undef HAVE_WAITPID