diff --git a/libc/include/sys/user.h b/libc/include/sys/user.h
index 5601b02..f9ad956 100644
--- a/libc/include/sys/user.h
+++ b/libc/include/sys/user.h
@@ -38,7 +38,7 @@
 #define PAGE_SIZE 4096
 #define PAGE_MASK (~(PAGE_SIZE - 1))
 
-#if __i386__
+#if defined(__i386__)
 
 struct user_fpregs_struct {
   long cwd;