FastMath tests fail with clang

Submitted by Christoph Hertzberg @chhtz

Assigned to Nobody

Link to original bugzilla bug (#1239)
Version: 3.3 (current stable)

Description

Before this stays unnoticed: clangs implementations of std::isinf and std::isnan appear to be unreliable. The easiest way for us would be to not use them for implementing the corresponding numext::isinf/isnan methods, but make hand-coded implementations.

Depends on

#1008 (closed)

Edited by David Tellenbach