Adjustments for AppleClang needed from Mojave onwards

See merge request !113

Incorporate generic building

See merge request !111

We have had issues with the build system using mtune=native to compile
the libsac2c and the runtime libraries, making it impossible to create
distributable packages without it breaking due to ISA incompatibilities.

Changing the build system to not use mtune=native is doable, but
involves having to filter out the mtune=native flag at the right points
in the build. Additionally, when using different C compilers (such as
with NVCC) we need to account for this, which may require a different
solution for each compiler. This is non-trivial to achieve as in some
instances the compiler is not applicable to build sac2c, but only a
runtime lib or two.

This commit uses a different method, which encodes the mtune=native flag
into sac2crc and adds a sac2c flag (`-generic`) to toggle the effect.
The advantage here is that we can define different flags for different
SBIs, without affecting the build system. Furthermore, the changes to
the build system are minimal, which involves propagating the flags to
sac2crc and change whether libsac2c is built with mtune=native or not.

Artem Shinkarov authored Oct 27, 2018 and Hans-Nikolai Viessmann committed Sep 05, 2019

    Previously we didn't compile runtime libraries like libsac,
    sacprelude, etc. with -mtune=generic.  As a consequence, all our
    packages are (very likely) incompatible with cpus other than
    of the host system.

    This commit fixes it.
Signed-off-by: Hans-Nikolai Viessmann <hv15@hw.ac.uk>

remove -pedantic flag from cmake

See merge request !110

We make use of a GCC system header marker to indicate that the
headerfile is not C standard compliant, and thus disable the warnings
relating to zero-argument variadic macros.

This commit also fixes a small mistake in config.cmake where we added
the no warning flag to the wrong var (oops).

EMR optimisation extension for CUDA backend

See merge request !108

This is a known issue with running a CMake built Makefile system
that eventually calls and External_Project. The various _steps_ in
the External_Project are **not** considered individual jobs with
interdependencies. This can therefor cause multiple instances of one
_step_ to be run, leading to undefined behavior. The issue is
documented in [1] and affects all versions of CMake > 3.10.

The workaround for this is to explicitly set dependencies on the _steps_
and remove DEPENDS from the External_Project.

[1]: https://gitlab.kitware.com/cmake/cmake/issues/18663

Macros perform similar purpose as phase driver (see phase.c), the
main difference is to decouple it away from just running phases
cyclically. Still uses counters, but the user controls what these
are.

User for minimize_transfers.c and algebraic_wlfi.c.

Some testing showed that the implementation was not ideal, leading to
problems in later CUDA traversals. I'm removing this, in favour of a
better implementation.

Completely forgot that EMRL is one by default, therefore whenever we
entered IWLMEM, we entered EMRTU, which in some very rare cases did
cause problems. We now check that the EMRCI and EMRTU flag is on as well!

Have moved out a function used in both traversals to the cuda_utils
module.

Also, I've removed the ISEMRLIFTED flag from EMRL/EMRTU, as it was
preventing certain cases from being identified (such as cond functions).

This optimisation works together with the CUDA IWLMEM optimisation to introduce
CUDA memory transfers into the AST. We need this traversal when using the EMR
optimisation as IWLMEM would otherwise lead to inoptimal code generation.

IWLMEM, when encountering a lift ERC, would within the loop function create a
host2device and cause a memory allocation and free on the CUDA device. The
EMRTU (EMR Type Update) traversal identifies such cases, and correclty
transforms the lifted ERCs into CUDA device_types *and* fixes the arguments of
the loop function applications (initial and recursi

We will use this later for EMRTU (relating to CUDA IWLMEM
optimisation).

The insert_memory_transfers module was split into several different
files (insert_withloop_memtran.c & insert_cudast_memtran.c) by Jing
starting from the 26-03-2010, and this was left in the git history.

This module is not used anywhere, and as far as I can tell, provides
nothing in addition to the other modules. As such its safe to remove the
files.

Additionally, I've identified the following libsac2c modules which are
also stale:

icm_betest.c
icm_trace.c
icm_comment.c
BEtest.c
wl_empty_result_handling.c
create_lac_fun.c
wl_descalarization.c
cuda_create_dfg.c
idag.c
elemqueue.c
elemlist.c
cygcompat.c
cygwinhelpers.c

One needs to take a closer look at this and see if they are still
useful.

Extend modulo primitive to support all "whole number" types

See merge request !107

Us `integral type` instead of `integer types`.

Additionally,
* we add an error when trying to use _mod_SxV_, _mod_VxS_, and _mod_VxV_
  which are not actually implemented.
* add a test to make sure _mod_SxS_ functions correctly.

[HOTFIX] fix incorrect assert check

See merge request !104

Remove Package Build to Seperate Project

See merge request !103

* also changed to the special `merge_request` specifier to build on
  MR creation and update.