diff --git a/crypto/mem_sec.c b/crypto/mem_sec.c
index 77bf165fbc555cbb85e155f56c2ccc709ad7d70a..ab4d137f633bdfa486b6290b51e0f2d7518ba970 100644
--- a/crypto/mem_sec.c
+++ b/crypto/mem_sec.c
@@ -45,6 +45,9 @@
 #ifndef PAGE_SIZE
 # define PAGE_SIZE    4096
 #endif
+#if !defined(MAP_ANON) && defined(MAP_ANONYMOUS)
+# define MAP_ANON MAP_ANONYMOUS
+#endif
 
 #ifdef IMPLEMENTED
 static size_t secure_mem_used;