[PATCH libcpp]: Avoid crash in interpret_float_suffix

[Tom Tromey]

>>>>> "Tristan" == Tristan Gingold <gingold@adacore.com> writes:

Tristan> 2012-05-04  Tristan Gingold  <gingold@adacore.com>
Tristan> 	* expr.c (interpret_float_suffix): Add a guard.

Ok.

Tom