bug#12687: 24.2.50; calc volume units conversion

[Edmund Kademan <ed@kademan.org>]

emacs -Q
C-x **    ;start calc
'gal RET  ;enter 1 gallon
uc        ;try to convert to new units

At this point calc should prompt for new units, but it does not.

A workaround for me is to redefine the math-get-standard-units
function:

*** calc-units.el	2012-10-19 17:35:54.000000000 -0400
--- calc-units-changed.el	2012-10-19 18:14:30.000000000 -0400
***************
*** 383,390 ****
  
  (defun math-get-standard-units (expr)
    "Return the standard units in EXPR."
!   (math-simplify-units
!    (math-extract-units
      (math-to-standard-units expr nil))))
  
  (defun math-get-units (expr)
--- 383,390 ----
  
  (defun math-get-standard-units (expr)
    "Return the standard units in EXPR."
!   (math-extract-units
!    (math-simplify-units
      (math-to-standard-units expr nil))))
  
  (defun math-get-units (expr)


In GNU Emacs 24.2.50.1 (i686-pc-linux-gnu, GTK+ Version 2.24.10)
 of 2012-10-19 on dl
Windowing system distributor `The X.Org Foundation', version 11.0.11103000
System Description:	Ubuntu 12.04.1 LTS

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