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

net/finger/describesyn.c

@@ -17,7 +17,7 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/fmt/itoa.h"
-#include "libc/intrin/bits.h"
+#include "libc/serialize.h"
 #include "net/finger/finger.h"
 
 /**

net/finger/finger.h

@@ -1,6 +1,5 @@
 #ifndef COSMOPOLITAN_NET_FINGER_FINGER_H_
 #define COSMOPOLITAN_NET_FINGER_FINGER_H_
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
 char *DescribeSyn(char *, size_t, const char *, size_t);
@@ -9,5 +8,4 @@ int GetSynFingerOs(uint32_t);
 uint32_t FingerSyn(const char *, size_t);
 
 COSMOPOLITAN_C_END_
-#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_NET_FINGER_FINGER_H_ */