Ensuring that double type is always evaluated at standard precision.
Ensuring that double type is always evaluated at standard precision.

Previously, GCC on x86 uses extended precision for intermediate
calculations by default.  This might conflict with njs_diyfp_t because
GCC is not always rounds back the intermediate values to standard
precision.

The fix is to explicitly tell to a compiler to do so.

This closes #507 issue on Github.

nginx/njs,nginx/njs,nginx/njs,nginx/njs,nginx/njs,nginx/njs