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-mips/asm/bitfield.h b/libc/kernel/uapi/asm-mips/asm/bitfield.h
index 4b8ac19..dbe56cc 100644
--- a/libc/kernel/uapi/asm-mips/asm/bitfield.h
+++ b/libc/kernel/uapi/asm-mips/asm/bitfield.h
@@ -18,6 +18,6 @@
  ****************************************************************************/
 #ifndef __UAPI_ASM_BITFIELD_H
 #define __UAPI_ASM_BITFIELD_H
-#define __BITFIELD_FIELD(field, more)   more   field;
+#define __BITFIELD_FIELD(field,more) more field;
 #endif
 /* WARNING: DO NOT EDIT, AUTO-GENERATED CODE - SEE TOP FOR INSTRUCTIONS */