bug#10763: 23.4; calc-embedded fails to simplify units in \frac

[Jeffrey Ratcliffe]

Using calc-embedded in LaTeX:

\documentclass[pdftex,a4paper]{report}
$ a \gets 3 m $
$ b \gets 4 m $
$ \evalto \alpha \gets \arcsin\left( \frac{a}{b} \right) \to
\arcsin\left( \frac{0.75 m}{m} \right) $
\end{document}

calc doesn't finish evaluating the expression, presumably because it
has failed to
simplify the units in the fraction.

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In GNU Emacs 23.4.2 (x86_64-pc-linux-gnu, GTK+ Version 2.22.1)
Windowing system distributor `The X.Org Foundation', version 11.0.70101000