Add init.c for initialization

This patch sets the environment variables that are needed during runtime for
the intepreter.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add stubs.c for stubbed functions

We add the stubs needed when "forking" processes.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add modules_config.c

This file is copied from a './Modules/config.c' of a Linux build and it contains
the modules init functions and their registration as Python extensions. We
commented the registration of the modules that we do not support yet. They
should be enabled back when we will add support for them by porting the
underlying native libraries.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

_sysconfigdata.py: Disable features that are not avaiable on Unikraft

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

_sysconfigdata.py: Introduce file

_sysconfigdata.py contains all the configuration data used by the interpreter at
runtime. This patch adds the slightly changed file generated by a ./configure
run.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

pyconfig.h: Disable features that are not avaiable on Unikraft

Some of these features have to enabled back when we will support them.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

pyconfig.h: Introduce file

pyconfig.h is generated when running ./configure and it contains the features
that are available on the build machine. This is copied from a local build.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

patches: Fix build issues

* Undefine HAVE_FORK and HAVE_EXECV
* Use pthread_t to unsigned long conversion

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Add Makefile.uk

In the original build, there are two kinds of sources: for core functionality
and for extensions. Each of them has a different set of compiler flags. In
order to emulate the same behavior, we define two libraries: 'python3-core' and
'python3-extensions'. Please notice that we still keep a 'python3' library as
the main logical library.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Introduce library skeleton

We use the BSD-3-Clause license for this library glue code.

Signed-off-by: Vlad-Andrei Badoiu <vlad_andrei.badoiu@stud.acs.upb.ro>
Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>
Reviewed-by: Felipe Huici <felipe.huici@neclab.eu>

Initial commit (empty)

Signed-off-by: Costin Lupu <costin.lupu@cs.pub.ro>