diff --git a/src/include/port/linux.h b/src/include/port/linux.h
index 283799c14d..f6aacc67ff 100644
--- a/src/include/port/linux.h
+++ b/src/include/port/linux.h
@@ -4,7 +4,7 @@
 #endif
 
 
-#if defined(__i386__)
+#if defined(__i386__) || defined(__x86_64__)
 typedef unsigned char slock_t;
 
 #define HAS_TEST_AND_SET