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/asm-x86/asm/ist.h b/libc/kernel/uapi/asm-x86/asm/ist.h
index 36d3c3d..27db89f 100644
--- a/libc/kernel/uapi/asm-x86/asm/ist.h
+++ b/libc/kernel/uapi/asm-x86/asm/ist.h
@@ -21,10 +21,10 @@
 #include <linux/types.h>
 struct ist_info {
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
- __u32 signature;
- __u32 command;
- __u32 event;
- __u32 perf_level;
+  __u32 signature;
+  __u32 command;
+  __u32 event;
+  __u32 perf_level;
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */
 };
 #endif