relibc: add missing POSIX/Linux headers and constants
New headers:
- include/sys/ioccom.h: Linux UAPI ioctl encoding macros (_IO/_IOR/_IOW/_IOWR)
- include/byteswap.h: bswap_16/32/64 inline functions
- src/header/sys_statfs/: struct statfs + statfs()/fstatfs() functions
(delegates to fstatvfs, converts to Linux struct statfs format)
New constants:
- sys_socket: MSG_NOSIGNAL, MSG_PROBE, MSG_CONFIRM, MSG_MORE, MSG_FASTOPEN
- sys_mman: MAP_GROWSDOWN, MAP_DENYWRITE, MAP_EXECUTABLE, MAP_LOCKED, MAP_NONBLOCK
- elf/cbindgen.toml: ELFMAG and SELFMAG #defines in after_includes
These headers eliminate the need for shim patches in libwayland (MSG_NOSIGNAL),
mesa (sys/ioccom.h), qtbase (sys/statfs.h, ELFMAG), pipewire/wireplumber
(byteswap.h, MAP_* flags).
Red Bear OS
32df50c8fa