See #1250

See #1250

Close #1239

The nanos_wg_wait_completion_mandatory does not check if the work group is in final mode. Therefore, it waits for unfinished tasks despite task creation should be avoided in final mode. This new API allows the support of GPU, FPGA, etc. tasks inside the final code created by Mercurium

Missed in commit 07401f5f

OpenCL tests now declare a weak symbol to enable the automatic feature
detection

Changing lower/upper bound types to allow int64_t; We discard to use any additional parameter in order to allow fully support of uint64_t type; fixes #1172

See 707bfcc2
See #1161

See #1161

Tests can still be passed before installation, as they now rely
on LD_LIBRARY_PATH environment variable.
Changing test generators to reflect this change.
Replacing old NANOS_DISABLE_ALLOCATOR macro by new NANOS_ENABLE_ALLOCATOR (missing replacements).

Fixed an error in api-omp-generator flags. Now it correctly links against OpenMP library, instead of linking with OmpSs.

Adapted memory allocator and tracker preprocessor guards to the new autoconf definitions.
Preprocessor '-include' flags are splitted in two: config.h is placed in CPPFLAGS, meanwhile new.hpp
is placed in CXXFLAGS. The reason is that some tests are written in C, thus using C++ headers results
in errors.