diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index aa68e7c..7fbed46 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -44,7 +44,7 @@
 # toolchain preprocessor
 kernel_default_arch_macros = {
     "arm": {},
-    "x86": {"__i386__": "1"},
+    "x86": {"__i386__": "1", "CONFIG_X86_32": "1"},
     }
 
 # Replace tokens in the output according to this mapping