- a partial selection from https://github.com/mrklein/openfoam-os-x
  with adjustments. The primary purpose is to reduce header-level
  incompatibilities and to provide a common set of make rules to allow
  easier patching (or re-integration).

- easier to ensure that flags are consistent

- initial settings for ADIOS2, linuxARM64Gcc, linuxARM64Clang

which may be optionally overridden by version-specific rules.

For example the default rules for gcc on GNU/Linux x86_64 are in the
wmake/rules/linux64Gcc directory.  If there is a need to change any of
the rules for a specific version of gcc, e.g. gcc-4.8.4 the directory
wmake/rules/linux64Gcc48 may be created into which any of the language
files may be provided containing the rules to override the defaults.

COMP: Fedore13 has linkage with --no-add-needed as default. This disallows indirectly loaded libraries.

- added rules for gcc-4.3 in preparation for switching to gcc-4.4

- added 'clean' target for wmake/src/Makefile
  It is probably reasonable to separate the binaries from the rules (TODO)