diff --git a/libbb/sysconf.c b/libbb/sysconf.c
index 4dbffbebd..031901980 100644
--- a/libbb/sysconf.c
+++ b/libbb/sysconf.c
@@ -8,7 +8,7 @@
  */
 #include "libbb.h"
 
-#if defined _SC_ARG_MAX
+#if !defined(ARG_MAX) && defined(_SC_ARG_MAX)
 unsigned FAST_FUNC bb_arg_max(void)
 {
 	return sysconf(_SC_ARG_MAX);