diff --git a/tool/build/lib/pml4t.h b/tool/build/lib/pml4t.h
index 4c23a5cd..5df471b5 100644
--- a/tool/build/lib/pml4t.h
+++ b/tool/build/lib/pml4t.h
@@ -1,5 +1,6 @@
 #ifndef COSMOPOLITAN_TOOL_BUILD_LIB_PML4T_H_
 #define COSMOPOLITAN_TOOL_BUILD_LIB_PML4T_H_
+#include "tool/build/lib/machine.h"
 #if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_