1. Circuitry that implements a given custom logic design, comprising: at least one multiplexer with an output, a plurality of inputs, and a plurality of transistors that have gate terminals, wherein a selected input of the plurality of inputs is directly connected to the output via a signal path, wherein the gate terminal of at least one of the transistors is hardwired to a ground power supply line, and wherein the plurality of transistors comprises: a first transistor having a first source-drain terminal that is directly connected to the signal path and having a second source-drain terminal that is not directly connected to the signal path; and a second transistor having a first source-drain terminal that is directly connected to the signal path and having a second source-drain terminal that is not directly connected to the signal path.