We need to create an initialized sigaction struct for Linux syscalls
thus its fields need to be public.

The field was named _restorer before but system libc/kernel uapi name the field
sa_restorer.

    - Copy 17 functions definitions from src/unix/mod.rs
      to src/unix/bsd/mod.rs src/unix/haiku/mod.rs
      src/unix/notbsd/linux/mod.rs and src/unix/solaris/mod.rs
    - Add some functions to android that was cfged out
    - Remove cf* and tc* functions implementations for android
      (they are available with api >= 12, which was release in 2011)