Replace __unused in kernel headers with __linux_unused to avoid
conflicts with __unused macro in sys/cdefs.h

Change-Id: Ice664397e0b7c7a90795012f30be5e43a9675525
diff --git a/libc/kernel/tools/defaults.py b/libc/kernel/tools/defaults.py
index 7eeffb4..6c7efd6 100644
--- a/libc/kernel/tools/defaults.py
+++ b/libc/kernel/tools/defaults.py
@@ -51,6 +51,7 @@
 # Replace tokens in the output according to this mapping
 kernel_token_replacements = {
     "asm": "__asm__",
+    "__unused": "__linux_unused", # The kernel usage of __unused conflicts with the macro defined in sys/cdefs.h
     }
 
 # this is the set of known static inline functions that we want to keep