bug#24533: 25.1; `c-token-at-point` wrong on floating point values

[Mohammed Sadik]

c-token-at-point doesn't returns the right value when the point
is on floating point numbers.

Eg. In the following statement, if I try to get the value of
`c-token-at-point` I get "55" ('|' is the point). But "23.55" is the
right value.

double length;
length = 23.5|5;

Thanks.

In GNU Emacs 25.1.1 (x86_64-redhat-linux-gnu, GTK+ Version 3.20.6)
 of 2016-07-25 built on buildhw-08.phx2.fedoraproject.org
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