diff --git a/C/lib/nl_alloc.c b/C/lib/nl_alloc.c
index 9e57b27..5ceec2f 100644
--- a/C/lib/nl_alloc.c
+++ b/C/lib/nl_alloc.c
@@ -8,6 +8,9 @@
 #define HDR_MAGIC 0xDEAD
 #define MMAP_THRESHOLD (ARENA_SIZE / 2) // 1 MB
 
+#ifndef MAP_PRIVATE
+#define MAP_PRIVATE 0x02
+#endif
 #ifndef MAP_ANONYMOUS
 #define MAP_ANONYMOUS 0x20
 #endif