Description: system wide scheme
 Implement system wide scheme:
 - sympow can be now called system wide as any regular executable;
 - precomputed plain data mesh files are kept in PKGDATADIR/datafiles
  (typically PKGDATADIR is /usr/share/sympow);
 - generated plain data mesh files are recorded in CACHEDIR/datafiles
  (by default CACHEDIR is HOME/.sympow);
 - binary data mesh files are created on the fly and stored in cache
   directories, the ones from the precomputed plain data mesh files are
	 stored in PKGCACHEDIR/datafiles/ENDIANTUPLE (typilcally PKGCACHEDIR
	 is /var/cache/sympow, and ENDIANTUPLE is a tuple characterizing the
	 architecture endianness or so for double floats) and the ones from the
	 generated plain data meshes are put in CACHEDIR/datafiles/ENDIANTUPLE;
 - the register data file param_data is in CACHEDIR/datafiles;
 - the data in CACHEDIR/datafiles are authoritative;
 - the employed script is in PKGLIBDIR (typically /usr/lib/sympow);
 - CACHEDIR, PKGCACHEDIR, PKGLIBDIR, and PKGDATADIR can be set via
   environment variables with their respective name prepended with
	 SYMPOW_ (it is recommended to set absolute paths whenever possible);
 - the basename of CACHEDIR must begin with `sympow' (typically `sympow');
 - CACHEDIR is created on the fly with respect to permissions and privileges
   whenever the following conditions are satisfied: (i) it terminates with at
	 least three directory separators (the creation is group-centric when the
	 number of separators is greater or equal to six, user-centric otherwise),
	 (ii) its parent directory exists (its basename either begins with `sympow'
	 or is implicitly assumed to be `sympow');
 - ENDIANTUPLE is set by default to bin.
Origin: vendor, Debian
Author: Jerome Benoit <calculus@rezozer.net>
Last-Update: 2016-12-26