[CMake] try_compile generates assertion failure in MSVC 2010

[Dominik Szczerba]

Many thanks for your feedback. Update:

- the proposed compiler switches do not solve the issue. Neither does /fp:strict
- bluntly ignoring the failing assertion (need to click twice) seems
to still produce some output. A bit scary though, no idea if the
numbers can be trusted...
- Indeed, the underlying problem is related to the exact predicates I
need to use (Shewchuk & co). As can be found in google, to force
double (and not extended) precision one needs:

fpu_init = _controlfp (0, 0), _controlfp (_PC_53, MCW_PC)

// do my fp computations to calculate various epsilons

_controlfp (fpu_init, 0xfffff)

So this clearly goes beyond cmake now, but of course if you have any
more ideas you are more than welcome to share them...

Regards,
Dominik