diff --git a/lib/system/alloc.nim b/lib/system/alloc.nim
index ff3e42fa14..c0b697238b 100644
--- a/lib/system/alloc.nim
+++ b/lib/system/alloc.nim
@@ -90,6 +90,8 @@ elif defined(posix):
     const MAP_ANONYMOUS = 0x1000
   elif defined(solaris):
     const MAP_ANONYMOUS = 0x100
+  elif defined(linux):
+    const MAP_ANONYMOUS = 0x20'i32
   else:
     var
       MAP_ANONYMOUS {.importc: "MAP_ANONYMOUS", header: "<sys/mman.h>".}: cint