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/virtio_9p.h b/libc/kernel/uapi/linux/virtio_9p.h
index 2adf0df..72bc64b 100644
--- a/libc/kernel/uapi/linux/virtio_9p.h
+++ b/libc/kernel/uapi/linux/virtio_9p.h
@@ -24,8 +24,8 @@
 #include <linux/virtio_config.h>
 #define VIRTIO_9P_MOUNT_TAG 0
 struct virtio_9p_config {
- __u16 tag_len;
+  __u16 tag_len;
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
- __u8 tag[0];
+  __u8 tag[0];
 } __attribute__((packed));
 #endif