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/maxmind/maxminddb.c

@@ -22,7 +22,7 @@
 #include "libc/calls/weirdtypes.h"
 #include "libc/errno.h"
 #include "libc/fmt/conv.h"
-#include "libc/intrin/bits.h"
+#include "libc/serialize.h"
 #include "libc/inttypes.h"
 #include "libc/limits.h"
 #include "libc/mem/mem.h"

third_party/maxmind/maxminddb.h

@@ -41,7 +41,6 @@
 #define MMDB_INVALID_NODE_NUMBER_ERROR             10
 #define MMDB_IPV6_LOOKUP_IN_IPV4_DATABASE_ERROR    11
 
-#if !(__ASSEMBLER__ + __LINKER__ + 0)
 COSMOPOLITAN_C_START_
 
 /* This is a pointer into the data section for a given IP address lookup */
@@ -178,5 +177,4 @@ const char *MMDB_strerror(int);
 const char *GetMetroName(int);
 
 COSMOPOLITAN_C_END_
-#endif /* !(__ASSEMBLER__ + __LINKER__ + 0) */
 #endif /* COSMOPOLITAN_THIRD_PARTY_MAXMIND_MAXMINDDB_H_ */