#!/bin/bash
s='#define FN_AUTO_FN_FNSECTOR   Function(2)     /* FN_ comment*/'
sed -E 's/.*[[:blank:]](FN[^[:blank:]]*)[[:blank:]]+[^[:blank:]]+\(([^()]*)\).*/\2:"\1",/' <<< "$s"
sed -E 's/.*\s(FN\S*)\s+\S+\(([^()]*)\).*/\2:"\1",/' <<< "$s"