Floating point rounding modes: we should restrict them slightly

[Don]

bearophile wrote:
> Walter Bright:
>> Yes, all the C functions will have to be gone through and separated. 
>> strlen() is safe, while strcpy() and printf() are not.
> 
> For some of the removed functions better C-like ones can be provided:
> http://www.ddj.com/cpp/214502214
> 
> Bye,
> bearophile

Just use D instead.