This commit introduces a UNIX-alike target for the l4re microkernel
operating system. While this system is not a UNIX system at all, it is
easiest to use the POSIX interface and hence benefit from common
definitions.

This version is a very early draft, only the basic data types have been
verified and most of the complex data types (structs and unions) have
not been ported yet.

Fixed the issues that prevented the libc_tests that are generated from passing. Also, fixed struct names and types to be representative of the linux source files.

hopefully that fixes build errors

overflow lines caused style build failure

somehow i didn't catch this on my machine...oversight

_GNU_SOURCE works differently than other libraries and creates
function pointer issues

semget, semop, semctl; semtimedop not implemented and struct semun not defined

also struct itimerval, which is necessary for the implementation

Also slightly modified argument name for localtime.

Fixed trailing whitespace in x86.rs and reverted the minor version number in the Cargo.toml

Added equivalents for user_regs_struct and user_struct from linux/user.h for x86 and x86_64.

The default  on OS X does not provide clear errors,
instead the NOCANCEL variants should be used. These are available
as of OS X 10.6 onwards.

There is a compatibility issue regarding the type of a flag parameter:
int vs uint. Linux does declare the syscall to use uint and musl
followed it, but it is incompatible with other POSIX recv*/send*
syscalls. So it seems to be wise to follow the glibc version of
prototypes with int.

Signed-off-by: NODA, Kai <nodakai@gmail.com>

Only for Linux and Android currently, though they also exist on BSDs