SINC - Return SINC(x) for as floats or as doubles

fsinc		return float value of sinc(x) for x input as a float
dsinc		return double precision sinc(x) for double precision x

Function Prototype:
float fsinc (float x);
double dsinc (double x);

Input:
x		value at which to evaluate sinc(x)

Returned: 	sinc(x)

Notes:
    sinc(x) = sin(PI*x)/(PI*x) 

Author:  Dave Hale, Colorado School of Mines, 06/02/89