Log Message:
Update to 3.7.3, from Jim Bernard in PR 19663.
Changes:
3.7.3
* Major: contributed code to re-add gamma, inverse normal, and
  inverse error function
* Windows specific fixes, most visibly changing the 'pause' command
  to avoid cpu hogging, and updated build procedures
* Improved metapost driver
* Make Linux driver work with devfs
* Numerous bugfixes backported from development version, see ChangeLog
* A large number of documentation misprints have been fixed

3.7.2
* Major: we have removed code that was labeled with a
  non-commercial use clause. The effect is that this
  removes the gamma, inverse normal, and inverse error
  function from platforms that have no native
  implementation.
* Support for BeOS
* New terminal drivers: emf (Enhanced Metafile Format),
  epslatex, ggi (General Graphics Interface), pdf, svg
 (W3C Scalable Vector Graphics)
* Updated png driver: web-friendly palette, transparent
  images, explicit colour specification
* Updated HPGL driver: optional multi-pen support,
  alternative plot sizes, variable font sizes
* Updated gnugraph driver: now requires GNU plotutils 2.2
  or better
* Updated eepic driver: picture environment now scales with
  "set size"
* Updated fig driver to fig file format 3.2
* Updated tkcanvas driver
* Fix font size option in pslatex driver
* configure-alike script for VMS
* Command substitution in double-quoted strings
* Vector clipping style for 2D plots
* Sort terminals by name before displaying
* Numerous bugfixes