This patch implements sys/user.h file that works for both x86_64 as well
as aarch64. This include file is used by sys/procfs.h which is needed
dependency for binutils. There is bug in this patch in aarch64 implementation
which is the lack of f128 implementation in rust, thus we can't create cbinding
for long double.

I faced many issues when compiling libstdC++-V3 and linking against
relibc mainly:
- Missing types (max_align_t)
- Different types definitions(ptrdiff_t , size_t)
- and the fact that wchar_t is part of standard C++ and it seams that we
  canno redefine standard types

libiconv expects program_invocation_name to be an lvalue

This makes relibc more compatible with other libc implementations

Without this the relibc tests would break. With this the relibc tests
pass and formerly breaking builds (such as uutils -> onig_sys) pass.

Typically with libc implementations, wchar_t and co are either defined
entirely by the libc or, under libc's arrangement, by headers supplied
by the compiler.

Things like dlmalloc in relibc need these definitions from relibc itself
and that's already already furnished by relibc's stddef.h.

These additional definitions here are redundant and collide with
compiler headers - for example: onig_sys (something that uutils depends
on) breaks. Instead, this patch makes the compiler headers define
things appropriately.

Add sys_timeb header

- Remove incorrect header styles
- Use export.replace where header style was previously needed
- Check compilation of tests using system gcc