util: add getbefloat64 As far as I can tell, this is wrong. double's format isn't strictly specified in the C standard, but the wikipedia article implies that platforms implementing optional Annex F "IEC 60559 floating-point arithmetic" will work correctly. My local C experts believe doing *((double *) &t) is a strict aliasing violation, and that using a union is also one. Doing memcpy appears to be the least-undefined behavior possible.