diff --git a/internal.h b/internal.h
index 1e42982..6804e2d 100644
--- a/internal.h
+++ b/internal.h
@@ -169,6 +169,9 @@
 extern long getNum (const char *cp);
 extern pid_t findInitPid();
 
+#if (__GLIBC__ < 2) && defined BB_SYSLOGD
+extern int vdprintf(int d, const char *format, va_list ap);
+#endif
 
 #if defined BB_MTAB
 #define whine_if_fstab_is_missing() {}