diff --git a/libc/include/llvm-libc-macros/limits-macros.h b/libc/include/llvm-libc-macros/limits-macros.h
index d4aa7ae539e8a..a4957225c9d34 100644
--- a/libc/include/llvm-libc-macros/limits-macros.h
+++ b/libc/include/llvm-libc-macros/limits-macros.h
@@ -235,4 +235,8 @@
 #define _POSIX_PATH_MAX 256
 #endif
 
+#ifndef _POSIX_ARG_MAX
+#define _POSIX_ARG_MAX 4096
+#endif
+
 #endif // LLVM_LIBC_MACROS_LIMITS_MACROS_H