OpenCoarrays 2.2.0: Bug fixes and enhancements

Notable Changes

Officially supported versions of GFortran are now 7.x and 8.2+

A number of compiler side issues were present in GFortran 8.1. Now that 8.2
has been released we are deprecating support for GFortran 6.x and earlier.
Officially supported versions of GCC/GFortran are 7.x and 8.2+. We anticipate
6.x will continue to mostly work for some time, however, we will be phasing
out support for GFortran 6 over time.

ISO_Fortran_binding and C portability issues in the last release (2.1.0)

• ISO_Fortran_binding (included in the last release) included some C code that
  was not portable. It now must be asked for explicitly by passing
  -DCAF_ENABLE_ISO_Fortran_BINDING:BOOL=ON when configuring with CMake.
  (If OPENCOARRAYS_DEVELOPER is set in the user's environment it will also
  default to turning on the build of ISO_Fortran_BINDING.)
• ISO_Fortran_binding has not been stripped out of OpenCoarrays, but it's use
  via OpenCoarrays is now deprecated and un-maintained; it will be stripped
  out at a later date.
• ISO_Fortran_binding has become its own package and is available from:
  https://github.com/sourceryinstitute/iso_fortran_binding

Bug Fixes

• Fixed #554: Allow building with clang, ensure no VLAs by default
  (ISO_Fortran_binding related)
• Fixed #538/#415: allocate_as_barrier_proc now passes consistently with
  GFortran7.4 and 8.2
• Fixed #515: Reallocate LHS issue when RHS is a coarray (off-by-one error)
• Fixed #563: Install.sh now sets user environment script to:
  • use DYLD_LIBRARY_PATH not LD_LIBRARY_PATH when on macOS and custom
    GFortran was installed
  • cleanup CMake PATH & prevent redundant modification of PATH
• Numerical instability in co_heat test fixed and pass condition made more
  rigorous
• Fixed #552: Checks for memory reallocation were incorrectly triggered by a
  singleton on 1st dim when referencing a coarray (delta == 1) in a derived
  type.
• Fixed #550: Conflicting types in the ISO_Fortran_binding tests
• CFI_SUCCESS value is now zero, consistent with the Fortran 2018 standard

Enhancements

• #565: cafrun now accepts -show in addition to -s and --show to mimic
  MPI wrappers. This now allows support from TAU Commander
• #520: When backed by OpenMPI, users may run entire configure, build, install
  and check process as root, but OpenMPI doesn't like to execute programs as root
  without an additional flag. Add --allow-run-as-root when running tests and
  using OpenMPI

Installation

Please see the installation instructions for more details on how to build and install this version of OpenCoarrays

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