diff --git a/libc/kernel/tools/clean_header.py b/libc/kernel/tools/clean_header.py
index 28cb05e..dad9120 100755
--- a/libc/kernel/tools/clean_header.py
+++ b/libc/kernel/tools/clean_header.py
@@ -71,6 +71,7 @@
     list.removeEmptyLines()
     list.removeMacroDefines( kernel_ignored_macros )
     list.insertDisclaimer( kernel.kernel_disclaimer )
+    list.replaceTokens( kernel_token_replacements )
 
     out = StringOutput()
     list.write(out)
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index b35f72b..ca7e6bb 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -43,6 +43,11 @@
     "x86": {"__i386__": "1"},
     }
 
+# Replace tokens in the output according to this mapping
+kernel_token_replacements = {
+    {"asm": "__asm__"},
+    }
+
 # this is the set of known static inline functions that we want to keep
 # in the final ARM headers. this is only used to keep optimized byteswapping
 # static functions and stuff like that.