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/udp.h b/libc/kernel/uapi/linux/udp.h
index 2c0819f..e1d546c 100644
--- a/libc/kernel/uapi/linux/udp.h
+++ b/libc/kernel/uapi/linux/udp.h
@@ -21,10 +21,10 @@
 #include <linux/types.h>
 struct udphdr {
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
- __be16 source;
- __be16 dest;
- __be16 len;
- __sum16 check;
+  __be16 source;
+  __be16 dest;
+  __be16 len;
+  __sum16 check;
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 };
 #define UDP_CORK 1