PR libstdc++/21193 (float, double, long double)
	* include/tr1/functional (hash<float>, hash<double>):
	Reimplement exploiting the Fnv_hash<>::hash helper.
	(hash<long double>): Reimplement using frexp (in this
	case, due to random padding bits, the former approach
	is not generally viable).


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@102043 138bc75d-0d04-0410-961f-82ee72b054a4