- now only needed when specify compiling -m32 on a 64-bit system.

  Internally use the __SIZEOF_LONG__ compiler macro (gcc, icc, llvm)
  to define when long is actually an int32_t.

- adjust copyright dates for manpages

- no use having wmkdepend on the target architecture when it will only
  be needed on the host architecture.

- remove make target for wmdep (flex-based scanner), which eliminates
  a bootstrap dependency on flex.

  As of OpenFOAM-v1806, wmdep has been superseded by wmdepend
  (ragel-based scanner).

- replace dirToString binary with shell/awk equivalent for simpler
  maintenance. The utility is very rarely used (auto scanning to
  create Make/files) so there is no performance difference.

- forces c++DBUG='-DFULLDEBUG -g -O0' for the compilation, to allow
  localized debugging during development without file editing and
  while retaining the WM_COMPILE_OPTION (eg, Opt)

  Note that switching between 'wmake' and 'wmake -debug' will not
  cause existing targets to be rebuilt. As before, these are driven by
  the dependencies. An intermediate wclean may thus be required.

- Eg, with surface writers now in surfMesh, there are fewer libraries
  depending on conversion and sampling.

COMP: regularize linkage ordering and avoid some implicit linkage (#1238)

- change internal naming from 'EXE_EXT' to 'EXT_EXE' for symmetry with
  'EXT_SO'

- fix typo in makefiles/info that affected wmake -show-compile-c

- additional safeguard in src/OpenFOAM/Make/options against self-linking.
  This is not normally required unless PROJECT_LIBS has been added into
  the link stage.

- replace (darwin) with (__APPLE__)
- replace (solarisGcc) with (__sun__ && __GNUC__)
- instead of 'darwin' -> '__APPLE'

- cease with passing a -D$(WM_ARCH) define since this adds no useful
  additional information and isn't used anywhere.

Reference
http://nadeausoftware.com/articles/2012/01/c_c_tip_how_use_compiler_predefined_macros_detect_operating_system

--

COMP: Extend size disambiguation on long (#1238)

- allows better separation from compiler settings

- use -fPIC instead of legacy -KPIC for intel compiler

solaris:
  - rename WM_ARCH from SunOS to solaris64 for consistency with wmake/rules
  - drop non-64 solaris from wmake/rules
  - remove automatic selection of FJMPI. This should be done in the bashrc
    or prefs.sh file instead.
  - remove old (likely inaccurate) exported flags, rely on wmake -show-xyz
    or user config instead

darwin:
  - remove '-Ddarwin' from the exported WM_CFLAGS, WM_CXXFLAGS.
    Not used elsewhere (ThirdParty)

- with the wmake rules we may have some compiler options bound to the
  internal compiler variable. For example,

     CC  = g++ -std=c++11 -m64

     c++FLAGS = ...

  So shift any flags from CC to CXXFLAGS for the output of
  'wmake -show-cxx', 'wmake -show-cxxflags', etc.

  This makes it much easier to handle the values correctly elsewhere.
  Eg,

      CXX="$(wmake -show-cxx)" CXXFLAGS="$(wmake -show-cxxflags)" \
         ./configure

- provide dedicated detection 'have_ptscotch' function that can be
  used after the 'have_scotch' function.

  It sets the PTSCOTCH_ARCH_PATH, PTSCOTCH_INC_DIR, PTSCOTCH_LIB_DIR
  and helps when the serial and parallel versions are located with
  different logic.

- add an additional test for wmake pre-processing

- can be useful for retrieving the compilation flags for use with other
  make systems (eg, cmake)

  * wmake -show-compile   (C++ not C)
  * wmake -show-cxx
  * wmake -show-cxxflags

- relocates some logic from makefiles/general into platform-specific
  overrides

- with -mcpu=native for automatic detection and -armpl for linking in
  the performance libraries

STYLE: relocate -mcpu into compiler instead of compiler-flags (#1225)

- with -mcpu=native for automatic detection and -armpl for linking in
  the performance libraries

- when windows portable executables (.exe or .dll) files are loaded,
  their dependent libraries not fully loaded. For OpenFOAM this means
  that the static constructors which are responsible for populating
  run-time selection tables are not triggered, and most of the run-time
  selectable models will simply not be available.

Possible Solution
=================

  Avoid this problem by defining an additional library symbol such as
  the following:

      extern "C" void libName_Load() {}

  in the respective library, and tag this symbol as 'unresolved' for
  the linker so that it will attempt to resolve it at run-time by
  loading the known libraries until it finds it. The link line would
  resemble the following:

      -L/some/path -llibName -ulibName_Load

  Pros:
    - Allows precise control of forced library loading

  Cons:
    - Moderately verbose adjustment of some source files (even with macro
      wrapping for the declaration).
    - Adjustment of numerous Make/options files and somewhat ad hoc
      in nature.
    - Requires additional care when implementing future libraries and/or
      applications.

  - This is the solution taken by the symscape patches (Richard Smith)

Possible Solution
=================

  Avoid this problem by simply force loading all linked libraries.
  This is done by "scraping" the information out of the respective
  Make/options file (after pre-processing) and using that to define
  the library list that will be passed to Foam::dlOpen() at run-time.

  Pros:
    - One-time (very) minimal adjustment of the sources and wmake toolchain
    - Automatically applies to future applications

  Cons:
    - Possibly larger memory footprint of application (since all dependent
      libraries are loaded).
    - Possible impact on startup time (while loading libraries)
    - More sensitive to build failures. Since the options files are
      read and modified based on the existence of the dependent
      libraries as a preprocessor step, if the libraries are initially
      unavailable for the first attempt at building the application,
      the dependencies will be inaccurate for later (successful) builds.

  - This is solution taken by the bluecape patches (Bruno Santos)

Adopted Solution
================

  The approach taken by Bruno was adopted in a modified form since
  this appears to be the most easily maintained.

Additional Notes
================

  It is always possible to solve this problem by defining a corresponding
  'libs (...)' entry in the case system/controlDict, which forces a dlOpen
  of the listed libraries. This is obviously less than ideal for large-scale
  changes, but can work to resolve an individual problem.

  The peldd utility (https://github.com/gsauthof/pe-util), which is
  also packaged as part of MXE could provide yet another alternative.
  Like ldd it can be used to determine the library dependencies of
  binaries or libraries. This information could be used to define an
  additional load layer for Windows.

- in addition to managing different vendors and versions, it may also
  be necessary or desirable to have a particular variant
  (eg, profiling, release, etc).

  Devise a new meaningful name for the variant and create a
  corresponding wmake rule.

  Eg, SYSTEMOPENMPI-profiling with a corresponding
      "wmake/rules/linux64Gcc/mplibSYSTEMOPENMPI-profiling" file
  that has suitable content for your system.

CONFIG: intel-mpi use intel64/ paths only for config and wmake rules (#1153)

- previously adjusted the config files, but missed the changes
  required for the wmake rules too.

  Now simply migrate to using  "intel64/{include,bin,lib}"
  instead of the older naming  "{include,bin,lib}64"

  These changes work since at least intel-mpi 2015 (5.x), but possibly
  earlier as well

- was WM_PROJECT_API in the environment and FOAM_API in dictionaries.

  Make these both consistently FOAM_API.
  This is a non-breaking change, since the value of WM_PROJECT_API
  (added in 1812) and/or FOAM_API is purely informative.
  For the current correct values, always use

    * foamEtcFile -show-api
    * wmakeBuildInfo -show-api

- Note: mpich now builds libmpi.so instead of libmpich.so

- define both -DMPICH_SKIP_MPICXX and -DOMPI_SKIP_MPICXX regardless of
  using openmpi or mpich. This simplifies the files and does not harm.

  - objectRegistry search, erase methods
  - clip, minMax
  - function object triggering
  ...

- older emacs tools into legacy
- old process tools

* Less frequently used scripts into bin/tools/

  - findEmptyMake
  - foamAllHC
  - foamUpdateCaseFileHeader

* Infrastructure file (only used by foamNewApp)

  - wmake/wmakeFilesAndOptions -> wmake/scripts/wmakeFilesAndOptions

* Merge wmakeRoot convenience as 'wmake -pwd'
* Remove obsolete wmakePrintBuild (superseded by wmakeBuildInfo)
* Remove unused mergeHistory file

- instead of

      WM_COMPILER=GccKNL WM_COMPILE_OPTION=Opt

      -> linux64GccKNLDPInt32Opt

  now specify

      WM_COMPILER=Gcc  WM_COMPILE_OPTION=OptKNL

      -> linux64GccDPInt32OptKNL

This makes it easier (and more obvious) for adding different tweaks
without needing to generate too many files.
Eg,

    cd wmake/rules/linux64Gcc

    cp cOpt   cOptBdw
    cp c++Opt c++OptBdw

    edit these two files and then use WM_COMPILE_OPTION=OptBdw

CONFIG: provide some default c/c++ flags in General compiler rules

- can make is easier when deriving new compile options, and ensures
  that '-02' is enabled as an initial default.

- finds the correct root directory location before creating
  the lnInclude directory

  Eg,

  from within something like src/finiteVolume/fields/fvPatchFields/..

      wmakeLnInclude -update -root

  it backtracks to find the top-level directory with Make/
  and makes the lnInclude directory there:

    Using /home/mark/openfoam/OpenFOAM-plus/src/finiteVolume
        ln: /home/mark/openfoam/OpenFOAM-plus/src/finiteVolume/lnInclude

- was for parallel compilation across multiple hosts, but less useful
  with modern CPUs with higher number of cores and/or hyperthreading.

  Fragile use and dependent on a 'lockfile' utility that is not often
  installed.