diff --git a/external/lua/loslib.c b/external/lua/loslib.c
index 0de66fa..017714f 100644
--- a/external/lua/loslib.c
+++ b/external/lua/loslib.c
@@ -408,7 +408,9 @@ static int os_exit (lua_State *L) {
   return 0;
 }
 
+#ifndef HOST_NAME_MAX
 #define HOST_NAME_MAX 256 /* according to POSIX */
+#endif
 
 /***
  * Returns the system hostname.
diff --git a/external/lua/patches/lua-5.4.6-oslib-hostname.diff b/external/lua/patches/lua-5.4.6-oslib-hostname.diff
index 7c0ee99..c587ce5 100644
--- a/external/lua/patches/lua-5.4.6-oslib-hostname.diff
+++ b/external/lua/patches/lua-5.4.6-oslib-hostname.diff
@@ -21,11 +21,13 @@
  #include <time.h>
  
  #include "lua.h"
-@@ -401,7 +408,26 @@
+@@ -401,7 +408,28 @@
    return 0;
  }
  
++#ifndef HOST_NAME_MAX
 +#define HOST_NAME_MAX 256 /* according to POSIX */
++#endif
  
 +/***
 + * Returns the system hostname.