sin, cos, other languages and DMD/LDC difference

[Philippe Sigaud]

> BTW, the differences in results is not due to optimization, but to dmd
> keeping intermediate results to 80 bits of precision, while other compilers
> are doing 64 bit precision on intermediate results.

OK, well noted. It also seems many languages silently use the same C
library to power their math calculation, hence the same results.