Switch kernel header parsing to python libclang

Replace the tokenizer in cpp.py with libclang.

Bug: 18937958
Change-Id: I27630904c6d2849418cd5ca3d3c612ec3078686d
diff --git a/libc/kernel/uapi/linux/mdio.h b/libc/kernel/uapi/linux/mdio.h
index 319670e..7766d11 100644
--- a/libc/kernel/uapi/linux/mdio.h
+++ b/libc/kernel/uapi/linux/mdio.h
@@ -272,5 +272,5 @@
 #define MDIO_PHY_ID_PRTAD 0x03e0
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 #define MDIO_PHY_ID_DEVAD 0x001f
-#define MDIO_PHY_ID_C45_MASK   (MDIO_PHY_ID_C45 | MDIO_PHY_ID_PRTAD | MDIO_PHY_ID_DEVAD)
+#define MDIO_PHY_ID_C45_MASK (MDIO_PHY_ID_C45 | MDIO_PHY_ID_PRTAD | MDIO_PHY_ID_DEVAD)
 #endif