Reduce header complexity

- Remove most __ASSEMBLER__ __LINKER__ ifdefs
- Rename libc/intrin/bits.h to libc/serialize.h
- Block pthread cancelation in fchmodat() polyfill
- Remove `clang-format off` statements in third_party

third_party/hiredis/alloc.c

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2020, Michael Grunder <michael dot grunder at gmail dot com>
  *

third_party/hiredis/alloc.h

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2020, Michael Grunder <michael dot grunder at gmail dot com>
  *

third_party/hiredis/async.c

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/async.h

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/async_private.inc

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/dict.c

@@ -1,4 +1,3 @@
-// clang-format off
 /* Hash table implementation.
  *
  * This file implements in memory hash tables with insert/del/replace/find/

third_party/hiredis/dict.h

@@ -1,4 +1,3 @@
-// clang-format off
 /* Hash table implementation.
  *
  * This file implements in memory hash tables with insert/del/replace/find/

third_party/hiredis/hiredis.c

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2014, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/hiredis.h

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2014, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/net.c

@@ -1,4 +1,3 @@
-// clang-format off
 /* Extracted from anet.c to work properly with Hiredis error reporting.
  *
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>

third_party/hiredis/net.h

@@ -1,4 +1,3 @@
-// clang-format off
 /* Extracted from anet.c to work properly with Hiredis error reporting.
  *
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>

third_party/hiredis/read.c

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/read.h

@@ -1,4 +1,3 @@
-// clang-format off
 /*
  * Copyright (c) 2009-2011, Salvatore Sanfilippo <antirez at gmail dot com>
  * Copyright (c) 2010-2011, Pieter Noordhuis <pcnoordhuis at gmail dot com>

third_party/hiredis/sds.c

@@ -1,4 +1,3 @@
-// clang-format off
 /* SDSLib 2.0 -- A C dynamic strings library
  *
  * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>

third_party/hiredis/sds.h

@@ -1,4 +1,3 @@
-// clang-format off
 /* SDSLib 2.0 -- A C dynamic strings library
  *
  * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>

third_party/hiredis/sdsalloc.h

@@ -1,4 +1,3 @@
-// clang-format off
 /* SDSLib 2.0 -- A C dynamic strings library
  *
  * Copyright (c) 2006-2015, Salvatore Sanfilippo <antirez at gmail dot com>