Switch almost all of Pal to Rusty error handling.

src/header/fcntl/mod.rs

src/header/stdio/mod.rs

src/header/stdlib/mod.rs

src/header/sys_file/mod.rs

src/header/sys_ioctl/linux.rs

src/header/sys_mman/mod.rs

src/header/sys_random/mod.rs

src/header/sys_resource/mod.rs

src/header/sys_stat/mod.rs

src/header/sys_statvfs/mod.rs

src/header/sys_time/mod.rs

src/header/sys_wait/mod.rs

src/header/time/mod.rs

src/header/unistd/mod.rs

src/header/utime/mod.rs

src/lib.rs

src/platform/allocator/sys.rs

src/platform/linux/mod.rs

src/platform/pal/mod.rs

src/platform/redox/mod.rs